Which of the following acts as a coenzyme in carboxylation reaction?

Ans. C. Biotin. (Ref Harper's Biochemistry 27th/Ch. 44).Vitamin B7 (biotin):Function:-Cofactor for carboxylation enzymes (which add a l-carbon group):- Pyruvate carboxylase: pyruvate (3C)*oxaloacetate (4C).- Acetyl-CoA carboxylase: acetyl-CoA (2C)*malonyl-CoA (3C).- Propionyl-CoA carboxylase: propionyl-CoA (3C)*methylmalonyl-CoA (4C).- 3 methylerotoyl CoA = methyl glutaconyl CoADEFICIENCY: due to antibiotic overuse, ingestion of raw eggs (avidin in egg white AVIDLY binds to biotin).Ch by Dermatitis, alopecia, enteritis.VitaminsVITAMINENZYMES IN WHICH IT ACTS AS COENZYMESDEFICIENCY DISEASE1. Vit. B1 (Thiamine)# Pyruvate dehydrogenase complex# Oxidation decarboxylation of a-keto-acid# Transketolase reaction# Tryptophan pyrolase# Beri-Beri disease# Werinicke encephalopathy2. Vit. B2 (Riboflavin) (heart stable but light sensitive)# FMN and FAD are two coenzymes of this vit.# Constituent of cytochrome -c- reductase# Warburg-yellow enzyme# Fumarate dehydroganase# Cheilosis# Glossitis# Seborrheic3. Vit. B3 (Niacin)# NAD and NADP are it's active forms with operate as hydrogen and electron transfer agents# They are co-enzymes for various types of dehydrogenase like- Alcohol dehyrogenase- Lactate dehydrogenase- Malate dehydrogenase- Pyruvate dehydrogenasePellagra C/B 3 D's:- Diarrhea- Dermatitis- Dementia4. Vit. B6 (Pyridoxine) (In vit.B6 defi Kynureine levels rise, which is converted to xanthurneic acid - a reliable criteria for B6 defi)# Co-transaminase# Co-decarboxylase# Deaminase# Involved in synthesis of Co-A# Coenzyme for Kynureninase# Epileptiform convulsion in infants# Sideroblastic anemia# (It is used in Rx of oxalate stone of kidney and homocytinuria)5. Pantothenic acid# Active form is Co-A# Formation of Acetyl CoA# Formation of succinyl CoA# Oxidation of F. acids# Synthesis of F. acids# G.I symptoms# Changed sleep pattern# Easy fatigue# Burning foot syndrome6. Biotin# Carboxylase enzyme (carboxylation reaction)# Leiner's disease# Exfoliative dermatitis7. Vit. B12 (Cyanocobalamine)# To convert-Methyl malonyl CoA|Homocysteine methionine|Ribonucleotide|DeoxyribounuleotideMethyl malonyluriaHomocystinuriaPernicious anemiaSACD