Enzyme Kinetics Quiz

Oxidoreductase

transfer of electrons from one molecule to another; redox reactions

Transferase

transfer of functional groups between two molecules

Hydrolase

single bond cleavage via addition of water; bond formation via the removal of water

Lyase

group elimination to form a double bond (can result in C-C bond cleavage)

Ligase

bond formation coupled to ATP cleavage (named in direction of ATP cleavage)

Isomerase

intramolecular rearrangements

Initial Velocity (Vo)

The fastest rate of a reaction, at the very beginning of the reaction before product has formed.

Maximum Velocity (Vmax)

The fastest rate of an enzymatically catalyzed reaction, achieved when all enzymes are saturated with substrate

Michaelis constant

the substrate concentration required for the initial velocity of a reaction to be ½ of the maximum velocity

Catalytic constant

Number of reactions catalyzed per enzyme per unit time; AKA turnover number

Oxidoreductase (systematic name)

Electron Donor: Electron Acceptor + Oxidoreductase (named in direction written)

Transferase (systematic name)

Reactant receiving functional group + functional group + transferase (named in direction written) (or kinase)

Hydrolase (systematic name)

Compound to be cleaved + hydrolase

Lyase (systematic name)

compound with single bond + lyase; if cleaving C-C bond, compound with single bond + synthase

Ligase (systematic name)

Both reactants + ligase OR compound formed + synthetase

Isomerase (systematic name)

reactant + isomerase

Vo

k2[ES]

Vmax

kcat[Etotal]

Km

(k-1+k2)/k1

kcat

Vmax/[E]total

Michael-Menten Equation

Vo\=Vmax[S]/Km+[S]

Assumptions of MME

Concentration of substrate is much greater than concentration of enzyme; The catalysis step (k2) is rate limiting; Reactions are at initial velocity; The Enzyme-Substrate complex is at steady state.