Unit 4 - Coenzymes

Question 1

Water soluble Vitamins

Answer 1

• B vitamins

- Vitamin C

Question 2

Vitamin B1

Answer 2

Chemical Name: Thiamine
Active Form: TTP
Function: metabolism of A.A.; coenzyme in oxidative decarboxylation of alpha-keto acids
Deficiency: Wernicke-Korsakoff syndrome ; Beriberi
Signs/Symptoms: loss of appetite, fatigue, constipation, depression, cardiovascular and muscular problems
Clinical significance: To see if extra thiamin is needed: typically alcoholics, excess antacid consumption, those on birth control or receiving hormone replacement therapy

Question 3

Vitamin B2

Answer 3

Chemical Name: Riboflavin
Active form: FMN, FAD
Function: in many oxidation-reduction reactions including: fatty acid oxidations, cirtic acid cycle, ETC, and deamination of a.a.
Deficiency: not life threatening
Signs/Symptoms: dermatits, seborrhea, lesions of skin, mouth, and tongue, photophobia
Clinical significance: Extra riboflavin needed by: pregnant women, women on birth control/hormone replacement therapy, alcoholics, those on antibiotics, or those with hypothyroidism

Question 4

Vitamin B3

Answer 4

Chemical Name: Niacin
Active form: NAD, NADH, NADP, NADPH
Function: involved as coenzymes in many redox reactions; NAD, NADH = catabolism reactions. NADP, NADPH = anabolism reactions
Deficiency: Pellagra
Signs/Symptoms: dermatitis, diarrhea, dementia, death
Clinical significance: deficiency common in areas where corn is main staple

Question 5

Vitamin B5

Answer 5

Chemical Name: Pantothenic Acid
Active in: coenzyme A and the acyl carrier protein
Function: involved in the synthesis of fatty acids, cholesterol, steroid hormones, acetylcholine, melatonin, and heme
Deficiency: Rare, result of Severe malnutrition
Signs/Symptoms: Burning foot syndrome

Question 6

Vitamin B6

Answer 6

Chemical Name: Pyridoxine, pyridoxal, pyridoxamine
Active form: pyridoxal phosphate
Function: coenzyme in metabolic reactions, especially of a.a. (transamination and deamination), fatty acid metabolism, synthesis of red blood cells, controls levels of homocysteine
Deficiency: Rare; seen in tuberculosis patients treated with isoniazid
Signs/Symptoms: irritability, nervousness, depression
Clinical significance: At risk people = alcoholics, women taking oral contraceptives, newborne nursing infants whose mothers are deficient in the vitamin

Question 7

Vitamin B12

Answer 7

Chemical Name: Cobalamine
Function: coenzyme necessary for synthesis of tetrahyrofolate, purine, pyrimide, nucleic acid, and methione (from homocysteine)
Deficiency: hyperhomocysteinemia, pernicious anemia

Question 8

Biotin

Answer 8

Name= a B vitamin
Function: coenzyme in carboxylation reactions, carrier of carbon dioxide
Deficiency: rare, but found in those that drink raw eggs
Signs/Symptoms: dermatitis, hair loss, loss of appetite, nausea

Question 9

Vitamin B9

Answer 9

Chemical Name: Folic acid
Active Form: THF = tetrahydrofolate
Function: carrier of one carbon atom in various biosynthetic reactions
Deficiency: hyperhomocysteinemia, neural tube defects, pernicious anemia

Question 10

Vitamin C

Answer 10

Function: synthesis of collagen, absorption of iron, antioxidant
Deficiency: Scurvy
Signs/Symptoms: weakening of connective tissue = sore, receding gums, loosening of teeth, bleeding, anemia, swollen joints

Question 11

Fat / Lipid soluble vitamins

Answer 11

• Vitamin A
• Vitamin D
• Vitamin E
• Vitamin K

Question 12

Vitamin A

Answer 12

Active form: retinal, retinol, and retinoic acid
Function: important in the cycle of vision
Deficiency: Xerophthalmia
Signs/Symptoms: night blindness or defective night vision

Question 13

Vitamin D

Answer 13

Chemical Name: D2 = ergocalciferol
D3 = cholecalciferol
Active form of D3 = calcitriol
Function: calcium and phosphate metabolism in GI tract and kidneys
Deficiency: Hypocalciemia, Rickets (children)
Signs/Symptoms: bowed limbs

Question 14

Vitamin E

Answer 14

Active form: alpha- tocopherol
Function: antioxidant against pollution and smoking, protect LDL from oxidation
Deficiency: primarily in premature infants; Retrolental fibroplasia (blindness due to improper oxygenation)
Signs/Symptoms: blindness, anemia, neurological disorders

Question 15

Vitamin K

Answer 15

Active form: requires chemical reaction (carboxylation)
Function: coenzyme in synthesis of prothrombin and other clotting factors
Deficiency: Rare because it is synthesized by intestinal bacterial
Clinical significance: Newborns administered vit K as preventative measure. Coumarin (Warfarin) = vit K antagonists