*OBJ - Enzymes & their classifications Flashcards
Explain why enzymes are called biological catalysts
- Enzymes provide the necessary environment for chemical reactions to progress at a reasonably faster rate - Remained unchanged - Dependent on pH, temp, concentrations, polarity, etc - But in human body pH = 7.4, temp = 37C and aqueous environment -> So need enzymes! - Different steps but same substrates & ending products
Distinguish between an uncatalyzed and a catalyzed reaction mechanistically
Uncatalyzed= slower or needed higher activation energy/different conditions Catalyzed = different steps but same product
Describe the structural and functional significance of an enzyme active site
Active site: region where substrate fits into, binds and the chemistry happens (some require cofactors/coenzymes) Mediated by enzyme side chains
Define the terms EP and ES in an enzyme catalyzed reaction
Enzyme -Substrate complex Enzyme-Product complex
Distinguish between substrate binding and substrate catalysis, and describe how both functions can be accomplished by the active site
a
Define cofactors and coenzymes; describe their roles in the active site of an enzyme
Apo enzyme - need a cofactor/enzyme Holoenzyme - enzyme with the cofactor/enzyme as a unit Cofactor: 1+ inorganic ions (1/3 of enzymes require metal ions for catalytic activity - Fe, Cu, Zn, Mn, Co) Coenzyme: organic of metallo-organic molecules that are carrier of specific functional groups (shuttles) **Both take part in substrate binding and/or in catalysis
Identify the active groups of the activation-transfer coenzymes (such as thiamine pyrophosphate, pyridoxal phosphate, coenzyme A, biotin) and oxidation-reduction coenzymes such as NAD+
Go over the mechanism of this table
& for Biotin
Summarize the different roles that metal ions can play in enzyme catalyzed reactions
Cofactor in substrate binding, catalysis, coordinated atom
List the six major classes of enzymatic reactions and identify the types of chemical reactions catalyzed by each of them
a
