Enzymes, Coenzymes, and Vitamins Review Chapter 18 Enzymes, Coenzymes, and Vitamins Review
Enzymes Catalysts for biological reactions Usually proteins Do not affect the equilibrium constant of a reaction. Lower the activation energy of a reaction. Usually proteins Examples: Catalase (catalyzes decomposition of H2O2) Papain (catalyzes protein hydrolysis)
Enzyme Cofactors Non-protein parts of enzymes that are essential for the catalytic activity of the enzyme. Metal ions Coenzymes Organic molecules (derived from vitamins) that act as enzyme cofactors
Vitamins Water-soluble vitamins Thiamine (vitamin B1) Deficiency causes beriberi (fatigue, poor appetite, weight loss, nerve degeneration, heart failure). Thiamine diphosphate (TPP) is a coenzyme in some decarboxylase enzymes. Dietary sources include liver, yeast, whole grains.
Vitamins Water-soluble vitamins Riboflavin (vitamin B2) Needed for good vision, healthy skin and hair. Flavin adenine dinucleotide (FAD) is a coenzyme in oxido-reductases. Dietary sources include liver, eggs, green vegetables, whole grains.
Vitamins Water-soluble vitamins Niacin (vitamin B3) Deficiency causes pellagra (dermatitis, muscle fatigue, mouth sores, mental disorders). Coenzymes include nicotinamide adenine dinucleotide (NAD+) and nicotinamide adenine dinucleotide phosphate (NADP+). Dietary sources include brewer’s yeast, meat, whole grains.
Vitamins Water-soluble vitamins Pantothenic acid (vitamin B5) Deficiency results in fatigue, retarded growth, anemia. A component of coenzyme A Dietary sources include brewer’s yeast, meat, eggs, whole grains.
Vitamins Water-soluble vitamins Pyridoxine (vitamin B6) Deficiency results in fatigue, dermatitis, anemia, retarded growth. Converted to the coenzyme pyridoxal phosphate (PLP). Dietary sources include meat, nuts, whole grains, spinach.
Vitamins Water-soluble vitamins Cyanocobalamine (vitamin B12) Deficiency causes pernicious anemia, neurodegeneration. A coenzyme in methyltransferases. Dietary sources include meats, fish.
Vitamins Water-soluble vitamins Ascorbic acid (vitamin C) Deficiency causes scurvy (bleeding gums, bruising), neurodegeneration. Dietary sources include fruits and vegetables.
Vitamins Water-soluble vitamins Biotin (vitamin H) Deficiency causes dermatitis, anorexia, depression. Dietary sources include yeast, liver, nuts, eggs.
Vitamins Water-soluble vitamins Folic acid (vitamin M) Deficiency causes dermatitis, anorexia, depression. Dietary sources include yeast, liver, green vegetables.
Vitamins Fat-soluble vitamins Retinol (vitamin A) Deficiency causes night blindness, dry skin. Dietary sources include yellow and green fruits and vegetables.
Vitamins Fat-soluble vitamins Cholecalciferol (vitamin D3) Deficiency causes rickets, osteomalacia. Dietary sources include cod liver oil, eggs, enriched dairy products.
Vitamins Fat-soluble vitamins Tocopherol (vitamin E) Deficiency causes hemolysis of red blood cells, anemia. Dietary sources include meat, whole grains, vegetables, vegetable oils.
Vitamins Fat-soluble vitamins Phylloquinone (vitamin K) Deficiency causes hemorrhage, delayed blood clotting. Dietary sources include liver, spinach, broccoli.
Vitamins