Associate Professor Department of Biochemistry Lecture-Coenzymes Dr. Saidunnisa Associate Professor Department of Biochemistry Lecture-Coenzymes

Learning Objectives At the end of the session student shall be able to : Define and classify coenzymes. Explain the biochemical role of coenzymes. Interpret their role in various disorders.

Coenzymes Some enzymes need assistance from other molecules (such as vitamins) in order to facilitate the transformation of chemical reactants into products. These other molecules are collectively referred to as coenzymes. These are heat stable, low-molecular weight, non protein organic substances function with enzymes in the catalytic processes.

Coenzymes are second substrates or co-substrates Most of them are derivatives of B-complex vitamins. The functional enzyme is referred to as holoenzyme which is made up of : Protein part (apoenzyme) Non protein part (coenzyme)

classification First group-take part in transfer of hydrogen atoms. (oxidoreductases) eg:-NAD/NADH+H,NADP/NADPH, FAD/FADH2,FMN/FMNH2 Second group -take part in transferring groups other than hydrogen. eg: PLP,TPP, Biotin, THF, Cobalamin.

First group Oxidative decarboxylation (PDH Complex)

First group First group Niacin Oxidation-reduction Pellagra NAD/NADP

First group Riboflavin (B2) FMN/FAD Oxidation-reduction Chelosis and glositis

Second group Pyridoxine (B6) Transamination PLP Neurological symptoms

Folic acid and B12 Coenzymes One carbon Isomerism

Oxidative decarboxylation Dry and wet beri beri Coenzyme Derived from Vitamin Physiologic function deficiency TPP Thiamine (B1) Oxidative decarboxylation Dry and wet beri beri FMN/FAD Riboflavin (B2) Oxidation-reduction Chelosis NAD/NADP Niacin Pellagra PLP Pyridoxine (B6) Transamination Neurological symptoms Biotin Carboxylation Alopecia/dry skin/dermatitis

Methyl/deoxyadenosyl cobalamine B12 Isomerism Coenzyme Derived from Vitamin Physiologic function deficiency Methyl/deoxyadenosyl cobalamine B12 Isomerism Megaloblastic anemia Tetrahydrofolate (THF) Folic acid One carbon metabolism Microcytic anemia Coenzyme A Pantothenic acid Acyl group Burning feet syndrome

Non-Vitamin coenzymes Abbreviation Biochemical Function Adenosine triphosphate ATP Donates phosphate Cytidine diphosphate CDP Required in phospholipid synthesis Uridine diphosphate UDP Required in glycogen synthesis S-adenosylmethionine SAM Donates methyl group Phosphoadenosine phosphosulfate PAPS