Enzymes II

Question 1

what is general acid base catalysis

Answer 1

ionizale R groups of active site serve as proteon donors and acceptors during reaction

Question 2

What is formation of covalent intermediates

Answer 2

transient formation of a covalent bond between the substreate and active site R groups

Question 3

how do metal ions paticipate in catalysis

Answer 3

postive charge stabilizes negatively charged intermediates
generates a nucleophile
bind to substrate

Question 4

examples of metaloenzymes

Answer 4

carbonic anhydrase

Question 5

what does carbonic anyhydrase contain

Answer 5

active site Zn2+ ion

Question 6

how does carbonic anhydrase act as a catalyze

Answer 6

Zn2+ binds to water and reduces pKa
faciliate OH- ion formation at physiologcial pH
CO2 binds active site
OH- attacks CO2 forming bicarb

Question 7

how does temperature affect reaction

Answer 7

rxn speeds up as temp incrases but at a certain point it denatures the enzyme

Question 8

v

Answer 8

rate of enzyme catalyzed reaction

Question 9

international units (U)

Answer 9

amoun tof enzyme required to convert 1 Mmol of substrate into product in 1 min at saturating substreate conc

Question 10

katal (kat)

Answer 10

amount of enzyme required to convert 1 mol of substrate into product in one second

Question 11

turnover number

Answer 11

the number of catalytic cycles that one enzyme molecule can perform in one second

Question 12

michaelis-menten graph

Answer 12

measures rate of product formation by a fixed amount of enzyme at diff. concentrations of substrate

Question 13

low Km indicates what

Answer 13

tight binding of substrate

Question 14

high Km indicates what

Answer 14

weaker binding of substrate

Question 15

what is late onset hyperammonemia caused by

Answer 15

mutations in OTCase

Question 16

what is the mutation in OTCase

Answer 16

R277W, replace of arginine with glutamine

Question 17

slope in lineweaver burk plot

Answer 17

Km/Vmax

Question 18

y in lineweaker burk plot

Answer 18

1/max

Question 19

when is x=1 in lineweaver burk plot

Answer 19

-1/Km

Question 20

reversible inhibitor

Answer 20

removal of inhibitor fully resotres enzyme actiity

Question 21

irreversible inhibotrs

Answer 21

remobal of inhinotr does not restore enzyme activity

Question 22

what is the most common type of reversible inhibotr

Answer 22

competivte

Question 23

how does competitive inhibor affect Km and Vmax

Answer 23

increases Km

doesn’t affect Vmax

Question 24

non-competitive inhibotr

Answer 24

bind at sites other than active site

Question 25

how does non-competitive inhibotr affect Vmax and Km

Answer 25

decrase Vmax

does not affect Km

Question 26

what are examples of competitive inhibotrs

Answer 26

acetaminophen, ibuprofen

Question 27

most drugs are waht

Answer 27

competitive inhbitors

Question 28

why would non-competitive inhibotors theortically make better drugs

Answer 28

they can inhibit enzyme acitive irrespective of substrate conc