Chemistry 104

Lecture #18: Enzymes

Read: pg. 595-610, 615-617, 619-620 and 623 (J.6)-626

HW: pg. 617-618 (1a,b,g, 2f,h, 3c,d, 4, (5 or 6), 12, 21, 22, 25-29, 31-34, 39)

pg. 629 (3,5,6,11-14)

Optional Reading: pg. 611-614 and 619-628

EXAM II on THURSDAY, NEXT CLASS (lectures #9-17).

HW is DUE next Tuesday. No HW is due on exam day

Optional HW Make-up Assignment: Today, 4:00, NSF 201

Two, 30 min seminars: Bacteria and Ulcers AND D-serine in the brain!

Objectives:

  1. Know that enzymes are typically globular proteins (fragile, water soluble proteins)
  2. Enzymes are catalysts. They increase rates of chemical reactions by lowering the energy of activation.
  3. Know how temperature, pH, substrate concentration [S], and enzyme concentration affect rates of enzyme catalyzed reactions.
  4. Be able to explain how enzyme activity depends on tertiary structure (of the enzyme).
  5. Know how ethanol works as an antidote in methanol poisoning.
  6. Know the types of reactions catalyzed by dehydrogenases, kinases, hydrolases (peptidases, lipases, carbohydrases).
  7. Two coenzymes, NAD+ and FAD are derived from vitamins.
  8. Nicotinamide (a component of NAD+) comes from niacin (nicotinic acid). FAD comes from riboflavin (vit B2). NAD+ and FAD are coenzymes in many redox reactions (ethanol, Embden-Meyerhof, Kreb’s cycle, fatty acid oxidation etc.). What function do you think these coenzymes serve in these reactions? (recall that oxidation and reduction always happen as a pair).

Vocabulary: enzyme, substrate, coenzyme, cofactor, in vivo, in vitro, competitive inhibition, allosterism, energy of activation, stereochemical specificity.