L23 BICH 440 ``

what is the goal of chymotrypsin in covalent and acid base catalysis, what tells us it’s an acid base mechanism, and what is involved

to hydrolyze a peptide bond via adding water

bell shaped pH dependence suggests an acid base mechanism

Ser, HIs, and Asp is involved

what is the mechanism used by chymotrypsin catalysis

covalent catalysis with acid base assistance

what is the Keq for many of kinases bound substrates and products

about 1

EAB →← EPQ

what are metals used for in enzyme catalysis

used to provide a source of powerful chemistry with their richness in electrons

• bound in specific motifs of amino acids

  • may be brought into enzyme in complex with substrate (like with ATP)

what is the electron isolater

heme

what is this structure

iron protoporphyrin IX

what is this

heme C

what is this

heme A

what type of electron transfer is seen with heme and what are the axial ligands and carrier

single e transfer → Fe (II)/ Fe(III)

often His/Met axial glands

carrier is O2

what is the electron splitter and when is it used and what can it do

flavin

• used in redox chemistry, especially in TCA cycle

  • can do hydride (2 electron/H+) and radical (1 electron) chemistry

what is the name of the two structures surrounded by brackets

outer bracket→ FAD

inner bracket → FMN

what is the name of this structure

NAD+

what is the difference between NAD+ and NADP+

the 2’ OH on the ribose sugar is esterified with a phosphate group

what reaction does NAD+/NADP+ go through to become NADH

the double espresso reaction

• 2 electron and one H+ transfer

what is this

pyruvate dehydrogenase complex

how does the pyruvate dehyrogenase complex work and what type of mechanism is this

the transferase leads to adding an H to both of the nitrogens in the rings

• ping pong mechanism

what is the enzyme known as the juggler, and what is its more common name

cobalamin, vitamin b12

what is this

cobalamin

step in oxidation of what type of carbon fatty acids involves free radical chemistry

odd carbon fatty acids

• done by coenzyme B12

what is the carbanion maker and what does it do

pyridoxal phosphate

• reaction is a component of amino acid biosynthesis

• unstable carbanion is hidden and staballized in the equilibrium with the quinonoid

what is this structure and what are the names for each form

pyridoxal phosphate

• carbanion → quinonoid intermediate

what are the flaps in protein chains that cover the active site used for

used as gates and are often the rate limiting step for the substrate binding and the product being released

symmetry in ASP protease (HIV protease) is broken by what

S or I binding

in HIV protease, is D25 or D125 the base or acid

D25 → acid (COOH)

D125 → base (COO-)

what type of enzyme is a liver alcohol dehydrogenase and what does it do

metalloenzyme

• catalyzes the transfer of a hydride (1 H and 2 e-) from NADH to acetaldehyde to form ethanol (and the reverse reaction)

  • the active site uses zinc ion to stabilize the negative charge development on the oxygen atom of acetaldehyde

what type of enzyme is carbonic anhydrase and what does it do

metalloenzyme

facilitates the rapid conversion of CO2 produced via cellular metabolism into bicarbonate

• enables its transport in the bloodstream and vice versa in the lung for exhalation

what type of reactions does long range electron transfer (tunneling) happen in

redox reactions