Enzymes II Flashcards
what is general acid base catalysis
ionizale R groups of active site serve as proteon donors and acceptors during reaction
What is formation of covalent intermediates
transient formation of a covalent bond between the substreate and active site R groups
how do metal ions paticipate in catalysis
postive charge stabilizes negatively charged intermediates
generates a nucleophile
bind to substrate
examples of metaloenzymes
carbonic anhydrase
what does carbonic anyhydrase contain
active site Zn2+ ion
how does carbonic anhydrase act as a catalyze
Zn2+ binds to water and reduces pKa
faciliate OH- ion formation at physiologcial pH
CO2 binds active site
OH- attacks CO2 forming bicarb
how does temperature affect reaction
rxn speeds up as temp incrases but at a certain point it denatures the enzyme
v
rate of enzyme catalyzed reaction
international units (U)
amoun tof enzyme required to convert 1 Mmol of substrate into product in 1 min at saturating substreate conc
katal (kat)
amount of enzyme required to convert 1 mol of substrate into product in one second
turnover number
the number of catalytic cycles that one enzyme molecule can perform in one second
michaelis-menten graph
measures rate of product formation by a fixed amount of enzyme at diff. concentrations of substrate
low Km indicates what
tight binding of substrate
high Km indicates what
weaker binding of substrate
what is late onset hyperammonemia caused by
mutations in OTCase
