Biochemistry Rapid Revision by Dr. Rajesh Jambhulkar [2 ed.]

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Appendix I : Abbreviations used in this Book

A Ab ACP ACTH Acyl CoA ADA ADH ADH ADP AFP AFLP Ag A/G AIDS ALA ALP ALT AMP ANF APC Apo-A AP sites AST AT ATCase ATP BAL BAO BHA BHT BMR BNP BOAA bp BP

adenine, adenosine antibody acyl carrier protein adrenocorticotropic hormone fatty acid derivative of coenzyme A adenosine deaminase alcohol dehydrogenase antidiuretic hormone adenosine diphosphate D-fetoprotein amplified fragment length polymorphism antigen albumin/globulin (ratio) acquired immunodeficiency syndrome G-aminolevulinic acid alkaline phosphatase alanine transaminase adenosine monophosphate atrial natriuretic factor antigen presenting cell apoprotein-A apurinic sites aspartate transaminase D1-antitrypsin aspartate transcarbamoylase adenosine triphosphate British antilewisite basal acid output butylated hydroxyanisole butylated hydroxy toluene basal metabolic rate brain natriuretic peptide E-oxalylaminoalanine base pair blood pressure

BPG

bisphosphoglycerate (2,3-BPG, 1,3-BPG) BSP bromosulphthalein BUN blood urea nitrogen BV biological value C cytosine, cytidine CA carbonic anhydrase Cal calorie Cam calmodulin cAMP 3’,5’-cyclic adenosine monophosphate (cyclic AMP) CAP catabolite activator protein CBG corticosteroid binding globulin CCK cholecystokinin cDNA complementary DNA cluster determinant antigen 4 CD4 CDP cytidine diphosphate CEA carcinoembryonic antigen CF cystic fibrosis CFTR cystic fibrosis transmembrane regulator cGMP 3’,5’-cyclic guanosine monophosphate CH constant heavy chain CHD coronary heart disease ChE cholinesterase Chl chlorophyll CL constant light chain CLIP corticotropin like intermediate lobe peptide CMP cytidine monophosphate CNS central nervous system CoA or CoASH coenzyme A COHb carboxyhemoglobin

751

752 COMT COPD

catechol-o-methyltransferase chronic obstructive pulmonary disease CoQ coenzyme Q (ubiquinone) CPK (CK) creatine phosphokinase (creatine kinase) CPPP cyclopentanoperhydrophenanthrene CPS carbamoyl phosphate synthase CRH corticotropin releasing hormone CS chorionic somatomammotropin CSF cerebrospinal fluid CT calcitonin CTP cytidine triphosphate dA deoxyadenosine dADP deoxyadenosine diphosphate DG diacylglycerol DAM diacetyl monoxime dAMP deoxyadenosine monophosphate dATP deoxyadenosine triphosphate dCMP deoxycytidine monophosphate DCT distal convoluted tubule DEAE diethyl aminoethylamine DFP or DIFP diidopropyl fluorophosphate dGMP deoxyguanosine monophosphate DHA docosahexaenoic acid DHAP dihydroxyacetone phosphate DHCC dihydroxycholecalciferol (1, 25DHCC; 24, 25-DHCC) DHEA dehydroepiandrosterone DHF dihydrofolate DHT dihydrotestosterone DIT diiodotyrosine dl deciliter DMB dimethyl benzimidazole DMS dimethyl sulfate DNA deoxyribonucleic acid DNase deoxyribonuclease DNMT DNA methyltransferase DNP 2, 4-dinitrophenol DOPA dihydroxy phenylalanine DPG diphosphoglycerate DPP dimethyl allyl pyrophosphate dTMP deoxythymidine monophosphate redox potential EO eAG estimated average glucose EC enzyme commission ECF extracellular fluid EDRF endothelium-derived releasing factor

BIOCHEMISTRY

EDTA EF EFA eIFs EGF ELISA EM ER ES ES cells E-site ETC FA Fab FAD FADH2 FAS F 1,6-BP F 2,6-BP Fc FDA FDNB FFA FGF FH4 FIGLU fMet FMN FMNH2 F 1-P F 6-P Fp FSH FTM G g 'G GABA GAG Gal-Cer GAR GDH GDP GFR GGT (GT) GH GHRH GIP GIT

ethylene diamine tetraacetate elongation factor essential fatty acids eukaryotic initiation factors epidermal growth factor enzyme-linked immunosorbent assay Embden-Meyerhof endoplasmic reticulum enzyme-substrate complex embryonic stem cells exist site electron transport chain fatty acid antigen binding fragment flavin adenine dinucleotide reduced FAD fatty acid synthase fructose 1, 6-bisphosphate fructose 2, 6-bisphosphate crystalline fragment food and drug administration 1-fluoro 2, 4-dinitrobenzene free fatty acid fibroblast growth factor tetrahydrofolate formiminoglutamic acid N-formylmethionine flavin mononucleotide reduced FMN fructose 1-phosphate fructose 6-phosphate flavoprotein follicle stimulating hormone fractional test meal guanine, guanosine gram free energy change J-aminobutyric acid glycosaminoglycans galactocerebroside glycinamide ribotide glutamate dehydrogenase guanosine diphosphate glomerular filtration rate J-glutamyl transpeptidase growth hormone growth hormone releasing hormone gastric inhibitory peptide gastrointestinal tract

Appendix I : ABBREVIATIONS USED IN THIS BOOK

Gla GLC Glu-Cer Gly GLUT GN GMP GnRH GRH GRIH G 6-P G 6-PD GPP GSH GSSG GTP GTT 'H HAC Hb HbA1 HbA1C HbF HbO2 HBsAg HbS hCG HDAC HDL HFCS HGPRT HGPS HIAA HIF HIV HLA HLH HMG CoA HMP HNPCC hnRNA Hp HPFH HPFH HPFC

J-carboxy glutamate gas liquid chromatography glucocerebroside glycine glucose transporters glucose-nitrogen (ratio) guanosine monophosphate gonadotropin releasing hormone growth hormone releasing hormone growth hormone release-inhibiting hormone glucose 6-phosphate glucose 6-phosphate dehydrogenase geranyl pyrophosphate glutathione (reduced form) glutathione (oxidized form) guanosine triphosphate glucose tolerance test change in enthalpy human artificial chromosome hemoglobin adult hemoglobin glycosylated hemoglobin fetal hemoglobin oxyhemoglobin hepatitis B surface antigen sickle-cell hemoglobin human chorionic gonadotropin histone deacetylase high density lipoproteins high fructose–corn syrups hypoxanthine guanine phosphoribosyltransferase Hutchinson-Gilford progeria syndrome hydroxy indole acetic acid hypoxia inducible transcription factor human immunodeficiency virus human leukocyte antigen helix-loop-helix E-hydroxy E-methylglutaryl CoA hexose monophosphate hereditary nonpolyposis colon cancer heterogeneous nuclear RNA haptoglobin hereditary persistence of fetal hemoglobin hereditary perristence of fetal hemoglobin hereditary persistence of fetal hemoglobin

HPLC HRE hs-CRP Hsp 5HT HTH ICD IDDM IDL IDP IF Ig IgG IGF IL IMP INH InsP2 (IP2) InsP3 (IP3) IPP IR ITP IU IV K KA Ka Kbp KD Keq D-KG Ki Km KJ LATS LCAT LDH LDL LFT LH LINES LPH LT Lp-a LSD M MAO MAO Mb

753 high performance liquid chromatography hormone responsive element high sensitive C-reactive protein heat shock protein 5-hydroxytryptamine helix-turn-helix isocitrate dehydrogenase insulin dependent diabetes mellitus intermediate density lipoproteins inosine diphosphate initiation factor immunoglobulin immunoglobulin G insulin-like growth factor interleukins inosine monophosphate isonicotinic acid hydrazide (isoniazid) inositol 1, 4-bisphosphate inositol 1, 4, 5-triphosphate isopentenyl pyrophosphate infrared inosine triphosphate international unit intravenous dissociation constant King Armstrong dissociation constant of acid kilo base pair kilodalton equilibrium constant D-ketoglutarate inhibition constant Michaelis constant kilojoule long acting thyroid stimulator lecithin cholesterol acyltransferase lactate dehydrogenase low density lipoproteins liver function tests luteinizing hormone Long interspesed elements lipotrophic hormone (lipotropin) leukotrienes lipoprotein-a lysergic acid diethylamide molar maximal acid output monoamine oxidase myoglobin

754 MbO2 MCAD MDH mEq mg MHC MI MIT mol mM mol. wt. mRNA MSH mtDNA MW NAD+ NADH NADP+ NADPH NAG NANA NDP NE NEFA ng NGF NIDDM NMP NMR NPN NPU OAA Ob OD OMP Osm PABA PAF PAGE PAH PAPS PBG PBI PCM PCNA

BIOCHEMISTRY

oxymyoglobin medium chain acyl CoA dehydrogenase malate dehydrogenase milliequivalents milligram major histocompatibility complex myocardial infarction monoiodotyrosine mole(s) millimolar molecular weight messenger RNA melanocyte stimulating hormone mitochondrial DNA molecular weight nicotinamide adenine dinucleotide reduced NAD+ nicotinamide adenine dinucleotide phosphate reduced NADP+ N-acetylglutamate N-acetylneuraminic acid nucleoside diphosphate niacin equivalents non esterified fatty acid nanogram (10–9 g) nerve growth factor non-insulin dependent diabetes mellitus nucleoside monophsphate nuclear magnetic resonance non-protein nitrogen net protein utilization oxaloacetate obese optical density orotidine monophosphate osmoles para amino benzoic acid platelet-activating factor polyacrylamide gel electrophoresis para amino hippurate phosphoadenosine phosphosulfate porphobilinogen protein bound iodine protein-calorie malnutrition proliferating cell nuclear antigen

pCO2 PCR PCT PDGF PDH PEG PEM PEP PER PEST PFK PG PGA pH PI Pi pI PIF PIP2 pKa PKU PL PLP PNA pO2 POMC PPi ppm PRIH PRL PRPP PT PTH PTH PUFA QPRT RACE RAIU RAPD ras RBC RBP RDA rDNA RE RER

partial presence of CO2 polymerase chain reaction proximal convoluted tubule platelet derived growth factor pyruvate dehydrogenase polyethylene glycol protein-energy malnutrition phosphoenol pyruvate protein efficiency ratio proline, glutamine, serine, threonine phosphofructokinase prostaglandins pteroyl glutamic acid negative log of (H+) phosphatidyl inositol inorganic phosphate isoelectric pH prolactin inhibitory factor inositol 4, 5-bisphosphate negative log of Ka phenylketonuria phospholipid pyridoxal phosphate peptide nucleic acid partial pressure of O2 pro-opiomelanocortin inorganic pyrophosphate parts per million prolactin release-inhibiting hormone prolactin 5-phosphoribosyl 1-pyrophosphate prothrombin time parathyroid hormone phenyl thiohydantoin polyunsaturated fatty acids quinolinate phosphoribosyltransferase rapid amplification of cDNA ends radioactive iodine uptake random amplified polymorphic DNA rat sarcoma red blood cells retinol binding protein recommended dietary (daily) allowance recombinant DNA retinol equivalents rough endoplasmic reticulum

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Appendix I : ABBREVIATIONS USED IN THIS BOOK

RF Rf RFC RFLP R-form RIA RMR RNA RNAP RNase R 5-P RPA RQ rRNA RSV RT rT3 SAM SCID SDA SdLDL Sf SGOT SGPT SHBG SIDS SINEs sn SNPs snRNA snRNP sRNA SRS STRs T T T3 T4 TBG TBPA TCA

releasing factor ratio of fronts replication factor C restriction fragment length polymorphism relaxed form radioimmunoassay resting metabolic rate ribonucleic acid RNA polymerase ribonuclease ribose 5-phosphate replication protein A respiratory quotient ribosomal RNA rouse sarcoma virus reverse transcriptase reverse T3 S-adenosylmethionine severe combined immunodeficiency specific dynamic action small dense low density lipoproteins Svedberg floatation serum glutamate oxaloacetate transaminase serum glutamate pyruvate transaminase sex hormone binding globulin sudden infant death syndrome short interspersed elements stereospecific number single nucleotide polymorphisms small nuclear RNA small nuclear ribonucleoprotein soluble RNA slow reacting substance simple tandem repeats thymine, thymidine thymus (T-lymphocyte) 3,5,3’-triiodothyronine 3,5,3’,5’-tetraiodothyronine (thyroxine) thyroxine binding globulin thyroxine binding prealbumin tricarboxylic acid

TF TFA T-form TG Tgb TGF THF TIBC TLC TLS Tm TMP TNF tPA TPP TRH tRNA TSH TX Pm UBG UCP UDP UDPG Pl PM UMP UTP UV VH VIP VL VLDL VMA Vmax VNTRs WBC XMP XP Xyl YAC

tissue factor trans fatty acids taut or tense form triacylglycerol thyroglobulin transforming growth factor tetrahydrofolate total iron binding capacity thin layer chromatography tumor lysis syndrome tubular maximum thymidine monophosphate tumor necrosis factor tissue plasminogen activator thiamine pyrophosphate thyrotropin releasing hormone transfer RNA thyroid stimulating hormone thromboxane micrometer (10–6 m) urobilinogen uncoupling protein uridine diphosphate uridine diphosphate glucose microliter (10–6 l) micromoles (10–6 M) uridine monophosphate uridine triphosphate ultraviolet variable heavy chain vasoactive intestinal peptide variable light chain very low density lipoproteins vanillyl mandelic acid velocity maximum variable number tandem repeats white blood cells xanthosine monophosphate xeroderma pigmentosum xylose yeast artificial chromosome

Appendix II : Origins of Important Biochemical Words

Acid (Latin) acidus–sour

Biology (Greek) bios–life; logos–discourse

Acidosis (Latin) acidus–sour; osis–condition

Bovine (Latin) bovinus–pertaining to cow or ox

Albinism (Greek) albino–white

Calorie (Latin) calor–heat

Alkali (Arabic) al-qite–ashes of saltwort

Cancer (Latin) crab

Allergy (Greek) allos–other; ergon–work

Carbohydrate carbo (Latin)–coal; hydor (Greek)– water

Alloseric (Greek) allo–the other

Caries (Latin)–decay

Amentia (Latin) amentis–mental deficiency

Casein (Latin) caseus–cheese

Amnesia (Greek) a–not; mnesis–memory

Catabolism (Greek) kata–down; ballein–to throw

Amphipathic (Greek) amphi–both; pathos–feeling

Catalysis (Greek) kata–down; lysis–degradation

Amphiphilic (Greek) amphi–both; philic–love

Cathepsin (Greek) to digest

Anaerobe (Greek) a–not; aer–air; bios–life

Cephalins (Greek) kephale–head

Anaplerotic (Greek) ana–up; plerotikos–to fill

Cheilitis (Greek) cheilos–lip; itis–inflammation

Androgen (Greek) aner–man; genesis–production

Cheilosis (Greek) cheilos–lip; osis–condition

Anemia (Greek) a–not; haima–blood

Chirality (Greek) cheir–hand

Anorexia (Greek) a–not; orexis–appetite coagulare

Chlorophyll (Greek) chloros–pale green; phyllon– leaf

(Greek) anti-against; metabole-

Cholelithiasis (Greek) chole–bile; lithos–stone; asis– condition

Anticoagulant anti (Greek)–against; (Latin)–to curdle Antimetabolite change

Arteriosclerosis arteria (Greek) hardening.

(Latin)–artery;

sclerosis

Cholesterol (Greek) chole–bile; sterol–solid alcohol Chromatography (Greek) chroma–colour; graphein –to write

Arthritis (Greek) arthron–joint; itis–inflammation

Chromosome (Greek) chroma–colour; soma–body

Atherosclerosis (Greek) athere–porridge; sclerosis– hardening

Chyle (Greek) chylos–juice

Beri-beri (Singhalese)–I cannot (said twice)

Chyluria (Greek) chylos–juice; auron–urine

Biochemistry (Greek) bios–life; chymos–juice

Chyme (Greek) chymos–juice 756

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Appendix II : ORIGINS OF IMPORTANT BIOCHEMICAL WORDS

Cirrhosis (Greek) condition

kirrhos–orange-tawny;

osis–

Cis (Latin) same side

Hepatitis (Greek) hepar–liver; itis–inflammation

Coagulation (Greek) coagulare–to curdle Collagen (Greek) produced

kolla–glue;

Hemoglobin haima (Greek)–blood; globus (Latin)– ball

genesthai–to

Hippos (Greek) horse be

Colloid (Greek) kolla–glue; eidos–form Consanguinity (Latin) con-with; sanguis–blood

Hormone (Greek) hormain–to excite Hydrophilic (Greek) hydro–water; philic–living Hydrophobic (Greek) hydro–water; phobic–hating

Creatine (Greek) kreas–flesh

Hyperglycemia (Greek) hyper–above; glycos-sweet; haima–blood

Cristae (Latin) crests

Hypertonic (Greek) hyper-above; tonos–tension

Cutaneous (Latin) cutis–skin Cytology (Greek) kytos–cell; logos–discourse

Hypoglycemia (Greek) hypo-below; glycos-sweet; haima–blood

Cytoplasm (Greek) kytos–cell; plassein–to mould

Hypotonic (Greek) hypo–below; tonos–tension

Dermatitis (Greek) derma–skin; itis–inflammation

Icterus (Greek) ikteros–jaundice

Diabetes mellitus (Greek) diabetes–running through (or a siphon); mellitus–sweet

Immunity (Latin) immunis–exempt from public burden

Dialysis (Greek) dia—through; lysis–loosening

Inflammation (Latin) inflammare–to set on fire

Doctor (Latin) docere—to teach

In situ (Latin) in the correct position

Eicosanoids (Greek) eikosi–twenty

Insulin (Latin) insula—island

Embolism (Greek) embolos–to plug

In vitro (Latin) in a test tube

Emphysema (Greek) emphysan–to inflate

In vivo (Latin) in the living tissue

Enkephalin (Greek) in the brain

Isomerism (Greek) iso-equal; mesos–part

Enthalpy (Greek) to warm within

Isotonic (Greek) iso–equal; tonos–tension

Entropy (Greek) in turning

Isotope (Greek) iso–equal; topos–place

Enzyme (Greek) in yeast

Jaundice (French) jaune–yellow

Erythrocyte (Greek) erythros–red; kytos–cell

Keratin (Greek) keras–horn

Eukaryotes (Greek) eu-true; karyon–nucleus Ferrous (Latin) ferrum–iron

Kwashiorkor (Ga-African) sickness of the deposed child

Folate (Latin) folium–leaf

Lactalbumin (Greek) lac-milk; albumin–white

Galactose (Greek) gala–milk

Lecithin (Greek) lekithos–egg yolk

Gastritis (Greek) gaster–belly; itis–inflammation

Lipids (Greek) lipos–fat

Gene (Greek) genesis–descent

Lactosuria lac (Latin)–milk; ovron (Greek)–urine

Genome (Greek) genos–birth

Leukocytes (Geek) leukos–white; kytos–cell

Globin (Latin) globus–ball

Leukoderma (Greek) leukos–white; derma–skin

Globulin (Latin) globulus—little ball

Ligase (Greek) ligate–to bind

Glossitis (Greek) glossa–tongue; itis–inflammation

Malaria (Italian) bad air

Glycolysis (Greek) glycos–sweet; lysis–dissolution

Malnutrition (Latin) nourishment

Goitre (Latin) gultur–throat Gonadotrophin (Greek) gona–generation; trophe– nourishment

malus–bad;

Marasmus (Greek) to waste Melanin (Greek) melan–black

nutrire–

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BIOCHEMISTRY

Menopause (Greek) men–month; pausis–stopping

Porphyrin (Greek) porphyra–purple colour

Metabolism (Greek) metabole–change

Post-prandial (Latin)–after food

Mitochondria (Greek) mitos–thread; chondros– granule

Prokaryotes (Greek) pro–before; karyon–nucleus

Mitosis (Greek) mitos–thread; osis–condition Monosaccharide (Greek)–mono–one; saccharin– sugar

Proteins (Greek) proteios–holding first place Rickets (Old English) wrickken–to twist Serum (Latin)–whey

Myeloma (Greek) myelos–marrow; oma–tumor

Sphingosine (Greek) sphingein–to bind tight

Myoglobin (Greek) myo–myscle

Steatorrhea (Greek) stear–fat; rheein–to flow

Nephritis (Greek) nephros–kidney; itis–inflammation

Stereoisomerism (Greek) stero-space

Neurosis (Greek) neuron–nerve; osis–condition

Sterol (Greek) steros–solid; ol- alcohol

Oedema or edema (Greek) oidema–swelling

Syndrome (Greek) syn–together; dramein–to run

Oligosaccharides (Greek) oligo–few; saccharon– sugar

Thalassemia (Greek) thalassa–sea

Osmosis (Greek)–push Osteomalacia (Greek) osteon–bone; malakia–softness

Thermodynamics (Greek) therme–heat; dynamics– power

Oxyntic (Greek) oxynein–to make acid

Thermogenesis (Greek) production

Oxytocin (Greek)–rapid birth

Thrombosis (Greek) thrombos–clot; osis–condition

Palindrome (Greek)–to run back again

Thylakoid (Greek) thylakos–a sac or pouch

Pantothenic acid (Greek) pantos–everywhere Pathogenesis (Greek) producing

pathos–disease;

genesis–

therme–heat;

genesis–

Tocopherol (Greek) tokos–child birth; pheros–to bear; ol–alcohol Trans (Latin) across

Pellagra (Italian)–rough skin

Tumor (Latin) swelling

Pepsin (Greek) pepsis–digestion

Vitamin (coined inappropriately in 1906) (Latin) vita–life; amine

Phagocytosis (Greek) phagein–to eat; kytos–cell; osis–condition Phobia (Greek) phobos–fear Polysaccharide (Greek) poly–many; saccharin– sugar

Xanthoma (Greek) xanthos–yellow Xenobiotics (Greek) xenos–strange Zwitterion (German) zwitter–hybrid.

Appendix III : Common Confusables in Biochemistry

Acetone; acetate – Acetone is a ketone; acetate is a carboxylic acid.

heme; bile salts are the sodium and potassium salts of bile acids (glycocholate, taurocholate) produced by cholesterol.

Acetyl CoA; acyl CoA – Acetyl CoA is a specific compound containing acetate bound to coenzyme A; acyl CoA is a general term used to refer to any fatty acid (acyl group) bound to coenzyme A.

Biliverdin; bilirubin – Both are bile pigments. Biliverdin is produced from heme in the reticuloendothelial cells; bilirubin is formed by reduction of biliverdin.

Albumin; albinism – Albumin is a serum protein; albinism is a genetic disease in tysosine metabolism.

Biotin; biocytin – Biotin is a B-complex vitamin; biocytin refers to the covalently bound biotin to enzymes (through H-amino group of lysine).

Amino; imino – Amino group ( NH2) is found in majority of amino acids; imino group ( NH) is present in a few amino acids like proline and hydroxyproline.

B-Lymphocytes; T-lymphocytes – B-lymphocytes produce immunoglobulins (antibodies) and are involved in humoral immunity; T-lymphocytes are responsible for cellular immunity.

Anabolism; catabolism – Anabolism refers to the biosynthetic reactions involving the formation of complex molecules from simpler ones; catabolism is concerned with the degradation of complex molecules to simpler ones with a concomitant release of energy.

Bisphosphate; diphosphate – Bisphosphate has two phosphates held separately e.g. 2,3-BPG; diphosphate has two phosphates linked together e.g. ADP.

Anomers; epimers – Anomers refer to two stereoisomers of a sugar that differ in configuration around a single carbonyl atom; epimers are two stereoisomers that differ in configuration around one asymmetric carbon of a sugar possessing two or more asymmetric carbon atoms.

Calcitriol; calcitonin – Calcitriol (1,25-DHCC) is the physiologically active form of vitamin D; calcitonin is a peptide hormone, synthesized by thyroid gland. Calorimetry; colorimetry – Calorimetry deals with the measurement of heat production by organism; colorimetry is concerned with the measurement of colour compounds.

Apoenzyme; coenzyme – Apoenzyme is the protein part of the functional enzyme (holoenzyme); coenzyme is the non-protein organic part associated with enzyme activity.

Carboxyl; carbonyl – These two are functional groups found in organic substances; carboxyl

Bile pigments; bile salts – Bile pigments (biliverdin, bilirubin) are the breakdown products of

Carnitine; creatine; creatinine – Carnitine transports activated fatty acids (acyl CoA) from

group

759

COOH; carbonyl

C .

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BIOCHEMISTRY

cytosol to mitochondria; creatine is mostly found in the muscle as creatine phosphate, a high energy compound; creatinine is the anhydride of creatine. Choline; cholic acid – Choline is a trimethyl quaternary base and is a constituent of acetylcholine; cholic acid is an important bile acid. Chyle; chyme – Chyle refers to lymph with milky appearance due to chylomicrons; chyme is the partially digested food in the stomach that passes to deodenum. Configuration; conformation – Configuration is the geometric relationship between a given set of atoms (e.g. L- and D-amino acids). Conformation is the special relationship of every atom in a molecule (e.g. secondary structure of protein). Cysteine; cystine – Both are sulfur containing nonessential amino acids. Cysteine contains sulfhydryl ( SH) group; cystine is formed by condensation of two cysteine residues and contains a disulfide ( S S ) group. Dextrins; dextrans; dextrose – The first two are polysaccharides composed of glucose. Dextrins are the breakdown products of starch; dextrans are gels produced by bacteria from glucose. Dextrose is glucose in solution (dextrorotatory) used in medical practice. Diabetes mellitus; diabetes insipidus – Diabetes mellitus is primarily an impairment in glucose metabolism due to the deficiency of, or inefficient insulin; diabetes insipidus is characterized by excretion of large volumes of urine (polyuria), caused by the deficiency of antidiuretic hormone (ADH). Endocytosis; exocytosis – Endocytosis is the intake of macromolecules by the cells; exocytosis refers to the release of macromolecules from the cells to the outside. Epinephrine; norepinephrine – Both are catecholamines synthesized from tyrosine. Epinephrine is methylated while norepinephrine does not contain a methyl group. Exons; introns – Exons are the DNA sequences coding for proteins; introns are the intervening DNA sequences that do not code for proteins. GABA; PABA – J-Aminobutyric acid (GABA) is a neurotransmitter; p-aminobenzoic acid (PABA) is a vitamin.

Gene; genome – A gene refers to the DNA fragment of a chromosome that codes for a single polypeptide; all the genes of a cell or an organism are collectively known as genome. Glu; Gla – Glu is the code for glutamic acid; Gla is the code for J-carboxy glutamic acid. Glucuronic acid; gluconic acid – Both are derived from glucose; oxidation of C6 results in glucuronic acid while oxidation of C1 yields gluconic acid. Glucuronic acid is produced in uronic acid pathway; gluconic acid is formed in hexose monophosphate shunt. Glutaric acid; glutamic acid – Glutaric acid is a dicarboxylic acid; glutamic acid (D-amino glutaric acid) is an amino acid. Glycogen; glycogenin – Glycogen is a storage form of carbohydrate (polysaccharide) in the animal body; glycogenin is a protein which serves as a primer for the initiation of glycogen synthesis. Glycoproteins; mucoproteins – Both are conjugated proteins containing carbohydrate as the prosthetic group. The term glycoprotein is used if the carbohydrate content is 4% carbohydrate. Hydrophilic; hydrophobic – Hydrophilic refers to affinity to water; hydrphobic means hatred towards water. Hypercalcemia; hyperkalemia – Elevation in serum calcium is hypercalcemia; increase in serum potassium is hyperkalemia. Hypocalcemia; hypokalemia – Hypocalcemia refers to a fall in serum calcium; hypokalemia is a decrease in serum potassium. Insulin; inulin – Insulin is a peptide hormone; inulin is a polysaccharide composed of fructose. In vivo; in vitro – In vivo refers to within the cell or organism; in vitro means in the test tube. Isoniazid; iproniazid – Isoniazid is an antituberculosis drug; iproniazid is an antidepressant drug. Lactam; lactim – These terms are used to represent tautomerism. Lactam indicates the existence of a molecule in keto form; lactim represents a molecule in enol form. Lactose; lactase; lactulose – Lactose is a disaccharide; lactase is an enzyme that cleaves lactose to glucose and gulactose; lactulose is a disaccharide containing galactose and fructose. Linoleic acid; linolenic acid – Both are 18 carbon unsaturated fatty acids. Linoleic acid has two double bonds; linolenic acid has three double bonds.

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Appendix III : COMMON CONFUSABLES IN BIOCHEMISTRY

Lipoproteins; lipotropic factors – Lipoproteins are molecular complexes composed of lipids and proteins; lipotropic factors are the substances (e.g. choline, betaine), the deficiency of which causes accumulation of fat in liver. E-Lipoprotein; E-lipotropin – E-Lipoprotein refers to the low density lipoproteins; E-lipotropin is a peptide hormone derived from proopiomelanocortin (POMC) peptide. Lyases; ligases – Lyases are the enzymes that catalyse the addition or removal of water, ammonia, CO2 etc.; ligases catalyse the synthetic reactions where two molecules are joined together. Malate; malonate; mevalonate – Malate is an intermediate in the citric acid cycle; malonate is a competitive inhibitor of the enzyme succinate dehydrogenase; mevalonate is an intermediate in cholesterol biosynthesis. Melanin; melatonin – Melanin is the pigment of skin and hair; melatonin is a hormone synthesized by pineal gland. Maltose; maltase – Maltose is a disaccharide; maltase is an enzyme that cleaves maltose to two molecules of glucose. Methyl, methenyl; methylene – All the three are one-carbon fragments as shown in brackets, methyl ( CH3); methenyl ( CH ); methylene ( CH2 ). Molarity; molality – Molarity is defined as the number of moles of a solute per liter solution; molality represents the number of moles of a solute per 1,000 g of solvent. Nicotinic acid; nicotine – Nicotinic acid is a B-complex vitamin; nicotine is an alkaloid present in tobacco leaves. Nucleoside; nucleotide – A nucleoside is composed of a nitrogen base and a sugar; nucleotide contains one or more phosphate groups bound to nucleoside. Oncogens; oncogenes – Oncogens are the chemicals that cause cancer; oncogenes are the genes causing cancer. Osmolarity; osmolality – Osmolarity represents osmotic pressure exerted by the number of moles (milli moles) per liter solution; osmolality refers to the osmotic pressure exerted by the number of moles (milli moles) per kg solvent. Oxidase; Oxygenase – Oxidase accepts O2 but oxygen atoms are not incorporated into substrate; oxygenase incorporates one or both oxygen atoms into substrate.

Palmitate; palmitoleate – Both are even chain (16-carbon) fatty acids. Palmitate is a saturated fatty acid; palmitoleate is a monounsaturated fatty acid. Phosphatase; phosphorylase – Phosphatase uses water to remove phosphoryl group; phosphorylase utilizes Pi to break a bond and produce a phosphorylated compound. Phosphatidyl ethanolamine; phosphatidal ethanolamine – Both are phospholipids. In phosphatidyl ethanolamine, the fatty acid is bound by an ester linkage. The fatty acid is held by an ether linkage in phosphatidal ethanolamine. Phytic acid; phytanic acid – Phytic acid is formed by the addition of six phosphate molecules to inositol, it is an inhibitor of the intestinal absorption of calcium and iron; phytanic acid is an unusal fatty acid derived from phytol, a constituent of chlorophyll. Prokaryotes; eukaryotes – Prokaryotes are the cells that lack a well defined nucleus; eukaryotes possess a well-defined nucleus. Prolamines; protamines – Both are simple proteins. Prolamines are soluble in alcohol; protamines are basic protein soluble in NH4OH. Pyridine; pyrimidine; pteridine – All the three are heterocyclic rings containing nitrogen, as depicted below. N

N

N N N Pyridine

N Pyrimidine

N Pteridine

Pyridine ring is found in niacin and pyridoxine; pyrimidine is present in thiamine (vitamin B1), thymine, cytosine and uracil; folic acid contains pteridine ring. Pyridoxine; pyridoxal – Pyridoxine is the primary alcohol form of vitamin B6; pyridoxal is the aldehyde form of B6. RDA; SDA – RDA (recommended dietary/daily allowance) represents the quantities of nutrients to be provided in the diet daily for maintenance of good health and physical efficiency; specific dynamic action (SDA) is the extra heat produced by the body over and above the caloric value of foodstuffs.

762 Renin; Rennin – Renin is synthesized by the kidneys and is involved in vasoconstriction causing hypertension; rennin is an enzyme found in gastric juice responsible for coagulation of milk. Ribosomes; ribozymes – Ribosomes are the sites of protein biosynthesis; ribozymes refer to the RNA molecules which function as enzymes. Retinol; retinal – Retinol is the alcohol form of vitamin A; retinal is the aldehyde form obtained by the oxidation of retinol. Scleroproteins; selenoproteins – Scleroproteins are a group of fibrous proteins; selenoproteins contain the amino acid selenocysteine. Serotonin; melatonin – Serotonin is a neurotransmitter synthesized from tryptophan; melatonin is a hormone derived from serotonin in the pineal gland. Somatotropin; somatostatin; somatomedin – Somatotropin is the other name for growth hormone (GH); growth hormone release inhibiting hormone (GRIH) is also called somatostatin; somatomedin refers to the insulin-like growth factor -I (IGF-I), produced by liver in response to GH action. Sucrose; sucrase – Sucrose is a disaccharide; sucrase is an enzyme that cleaves sucrose to glucose and fructose.

BIOCHEMISTRY

Synthase; synthetase – Both the enzymes are concerned with biosynthetic reactions. Synthase does not require ATP; synthetase is dependent on ATP for energy supply. (Note : This distinction between synthase and synthetase however, is not maintained strictly by most authors). Thiamine; thymine – Thiamine is a vitamin (B1); thymine is a pyrimidine base found in DNA structure. Thiokinase; thiolase – Thiokinase activates fatty acids to acyl CoA; Thiolase catalyses the final reaction in E-oxidation to liberate acetyl CoA from acyl CoA. Transcription; translation – Transcription refers to the synthesis of RNA from DNA; translation involves the protein synthesis from the RNA. Uric acid; uronic acid – Uric acid is the end product of purine metabolism; uronic acids are formed by the oxidation of aldehyde group of monosaccharides (e.g. glucuronic acid). Ureotelic; uricotelic – Ureotelic organisms (e.g. mammals) convert NH3 to urea; uricotelic organisms (e.g. reptiles) convert NH3 to uric acid. Vitamin A; coenzyme A – Vitamin A is fat soluble vitamin; coenzyme A is derived from water soluble vitamin, pantothenic acid.