Biochemistry--Vitamins, Coenzymes, and Diseases

Essential Ions

Metal ions involved in enzyme activity. Two categories:

Metaloenzymes: Transition metals (i.e. Fe 2+) that are tightly bound to enzyme and directly participate in enzyme catalysis, usually as part of redox reactions.

Activator Ions (Metal activated enzmes): Loosly bound group 1 & 2 metals that do not directly participate in catalysis, but help align substrates and shield enzyme from charges

Coenzymes

Organic cofactors, usally derived from nutritional vitamins. Two categories:

Cosubstrates (loosely bound), gets altered and then goes on its merry way, e.g. ATP donates a phosphate group then leaves as Adp

Prosthetic Groups (tightly bound), e.g. Heme groups

fat soluable vitamins include

A, D, E, K

Hydrophobic in nature, so dissolve in lipids

Generally stick around much longer than water soluable because harder to excrete

Easier to overdose on than water soluable

Scurvy

A Disease caused by vitamin C deficiency, AKA Ascorbate deficiency

Historically was found in sailors/pirates without access to fresh fruits and vegetables. Solved by citrus rations, i.e. "Limeys"

Symptoms include fatigue, lethergy, anemia, poor wound healing, bleeding; body can't produce new collagen

Beriberi

the thiamin-deficiency disease; characterized by loss of sensation in the hands and feet, muscular weakness, advancing paralysis, and abnormal heart action

Thiamine is coenzyme of citric acid cycle (pyruvate decarboxylase) and also needed to produce neurotransmitters

Wernicke-Korsakoff Syndrome

Growth Retardation

Associated with Riboflavin (B2) Deficiency

Pellagra

the niacin (B3)-deficiency disease, characterized by diarrhea, dermatitis, dementia, and eventually death

Dermititis in Chickens

Pantothenate (B5) Deficiency

Dermititis in Rats

Pyridoxal (B6) Deficiency

Adenosine Triphosphate (ATP)

Cosubstrate

Donation of Phosphoryl or Nucleotidyl Groups

No Associated Vitamin

S-adenosylmethionine

Adenosine + Ribose + Mithionine

Co Substrate

Donation of Methyl Group

No associated Vitamin

Uridine diphosphate glucose

Uracil + 2 Phosphates + Glucose

Cosubstrate

Transfer of Glycosyl groups

No Associated Vitamin

nicotinamide adenine dinucleotide (NAD+)

&

nicotinamide adenine dinucleotide Phosphate (NADP+)

Adenine + Ribose + 2 Phosphates + Ribose + Nicotinamide

Cosubstrate

Redox reactions involving 2 electron transfer; Glycolysis and TCA--Give e- to electron transport chain

Source is Vitamin B3 / Niacin

Flavin mononucleotide (FMN)

&

Flavin Adenin Dinucleotide (FAD)

Prosthetic Group

Redox Reactions Involving 1-2 e- transfers

Source is Vitamin B2 / Riboflavin

Coenzyme A (Acetyl COA)

Cosubstrate

Transfers Acyl Groups

Source is Vitamin B5 / Pantothenate

Thiamine Pyrophosphate (TPP)

Prosthetic Group

Transfer of multi-carbon fragments containing a carbonyl group

Source is Vitamin B1 / Thiamine

pyridoxal phosphate

Prosthetic Group

Transfer of Groups to and from amino acids

Source is Vitamin B6 / Pyridoxine

Biotin

Prosthetic Group

ATP-Dependent carboxylation of substrates or transfer of carboyl groups between substrates

Source: Vitamin B7 / Biotin

Tetrahydrofolate

Cosubstrate

Transfer 1-carbon groups, e.g. the methylation of DNA

Source: Folate

Cobalamin

Prosthetic Group

Intramolecular rearrangements, transfer of methyl groups.

Source; Vitamin B12 / Cobalamin

Retinal

Prosthetic Group

Essential for Vision

Source: Vitamin A

Vitamin K

Prosthetic Group

Carboxylation of some glutamate residues; clotting factors

Source: Vitamin K

Ubiquinone (coenzyme Q)

Cosubstrate

Lipid-Soluable Electron Carrier

No Vitamin Source

Heme group

Prosthetic Group

Electron Transfer

No Vitamin Source