Humboldt State University ® Department of Chemistry

Richard A. Paselk

Chem 438 - Introductory Biochemistry - Spring 2013

Lecture Notes:

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Enzyme Catalysis, cont.

Chymotrypsin

(digestive enzyme).

Zymogens

Introduction to Vitamins and Cofactors

Terms:

Let's start with a brief overview of the names, structures and physiological functions of the common vitamins as shown on the Slide: Niacin, Riboflavin [B2], Thiamine, Pantothenic acid, Biotin, Pyridoxal [B6], Folic acid, Lipoic acid, Cobalamin [B12], L-Ascorbic acid [C], and the lipid soluble vitamins A, D, E, and K). Fun facts:

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Data and most vitamin structures courtesy of Wikipedia Commons article on Vitamins and links to individual vitamins

Vitamin generic descriptor name Vitamer chemical name(s) (list not complete Solubility Structure Diagram Recommended dietary allowances (male, age 19–70)[ Deficiency disease Upper Intake Level (UL/day) Overdose disease
Vitamin B1 Thiamine Water Thiamine structure diagram 1.2 mg Beriberi, Wernicke-Korsakoff syndrome N/D[20] Drowsiness or muscle relaxation with large doses.[21]
Vitamin B2 Riboflavin Water Riboflavin structure diagram 1.3 mg Ariboflavinosis N/D
Vitamin B3 Niacin, niacinamide Water Niacin structure diagram 16.0 mg Pellagra 35.0 mg Liver damage (doses > 2g/day)[22] and other problems
Vitamin B5 Pantothenic acid Water Pantothenic acidstructure diagram 5.0 mg[23] Paresthesia N/D Diarrhea; possibly nausea and heartburn.[24]
Vitamin B6 Pyridoxine, pyridoxamine, pyridoxal Water Pyridoxal-P structure diagram 1.3–1.7 mg Anemia[25] peripheral neuropathy. 100 mg Impairment of proprioception, nerve damage (doses > 100 mg/day)
Vitamin B7 Biotin Water Biotin structure diagram 30.0 µg Dermatitis, enteritis N/D
Vitamin B9 Folic acid, folinic acid Water Folate structure diagram 400 µg Megaloblast and Deficiency during pregnancy is associated with birth defects, such as neural tube defects 1,000 µg May mask symptoms of vitamin B12 deficiency; other effects.
Vitamin B12 Cyanocobalamin, hydroxycobalamin, methylcobalamin Water Coballamin structure diagram 2.4 µg Megaloblastic anemia[26] N/D Acne-like rash [causality is not conclusively established].
Vitamin C Ascorbic acid Water Ascorbic acid structure diagram 90.0 mg Scurvy 2,000 mg Vitamin C megadosage
Vitamin A Retinol, retinal, and four carotenoids including beta carotene Fat retinol structure diagram 900 µg Night-blindness, Hyperkeratosis, and Keratomalacia[19] 3,000 µg Hypervitaminosis A
Vitamin D Ergocalciferol, cholecalciferol Fat Cholecalciferol structure diagram 5.0 µg–10 µg[27] Rickets and Osteomalacia 50 µg Hypervitaminosis D
Vitamin E Tocopherols, tocotrienols Fat alpha-tocopherol structure diagram 15.0 mg Deficiency is very rare; mild hemolytic anemia in newborn infants.[28] 1,000 mg Increased congestive heart failure seen in one large randomized study.[29]
Vitamin K phylloquinone, menaquinones Fat Vit K structure diagram 120 µg Bleeding diathesis N/D Increases coagulation in patients taking warfarin.[30]

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© R. A. Paselk 2010;

Last modified 28 February 2013