exam one cram notecards

Question 1

isolectric point and anion exchange

Answer 1

Pi>pH:protein is positively charged and will bind to cation exchange
pH>Pi: Protein is negativelt charged will bind to anion exchange

Question 2

Ramachandran

Answer 2

Axis: X:psi, Y:phi
Gly: no restriction
Pro: restriction

Question 3

Competitive inhibition

Answer 3

Binds to enzyme, changes slope and Km but not y int
multiply Km by alpha

Question 4

uncompetitive inhibiton

Answer 4

binds to ES, same slope dif Y int and Km. a’/Vmax

Question 5

noncompettivie

Answer 5

Both things,

Question 6

a helix numbers

Answer 6

1.5 Angstroms/residue
3.6 residues per term

Question 7

Cholera toxin symmetry

Answer 7

C5 symmetry

Question 8

GroEL symmetry

Answer 8

C7

Question 9

Where does trypsin cut? chemotrypsin?

Answer 9

Trypsin: Lys, Arg
Chemotryp: Try, trp, phe, leu
BOTH BLOCKED BY PROLINE

Question 10

hemoglobin symmetry

Answer 10

C2

Question 11

HIll coefficient

Answer 11

If hill>1=cooperative
if hill<1=not cooperative

Question 12

bohr effect on hb

Answer 12

ph decrease, histidine protonated, salt bridge stronger, decrease O2 binding, more o2 to muscles. Shifts sigmoidal curve left

Question 13

BPG

Answer 13

Shifts curve right
decreases HB affinity for O2, increases 02 delivery to tissue

Question 14

RNase A mechanism

Answer 14

histidines carry out the acid base catalysis
1. his acts as base, takes H+ from 2 OH
2. O-nucleophillic attack
3. histidind 2 acts as acid, gives H+
4. 2,3 cyclic intermediate formed

Then
1. histidine2 acts as base, takes H+ from H2O
2. water OH is nucleophile, attakcs phosphate intermediate
3. his 1 acts as acid, gives H+
4. 2nd product formed

Question 15

metal ion catalysis

Answer 15

Zinc coordinated by three histidines
zn polarizes H2O which ionizes bc the 4th histidine
OH nucleophillic attack on C of CO2
bicarbonate formed

Question 16

covalent catalysis

Answer 16

cov bond is temporarily formed between enzyme and substrate

Question 17

Trypsin

Answer 17

-All B protein
similar to chymotrpysin and elastase, same cat triad but diff specificity

Question 18

Catalytic triad

Answer 18

Aspartate: orients histadine
histadine:under goes acid base catalysis
serine: does covalent catalysis

Question 19

Features of serine protease mechanism

Answer 19

covalent catalysis to create a covalent intermediate (tetrahedral)
concerted acid base catalysis
transition state stabilization via the oxyanion hole
covalent bond formation that transiently turns trigonal C to tetrahedral intermediate
tetrahedral oxyanion intermediate that stabilizes the transition state

Question 20

ATCase

Answer 20

12 subunits, D3 symmetry
feeback inhibited by CTP
ATP stimulates ATCase
CTP binds T state(less active)
ATP binds R state(more active)
PALA shifts T->R

Question 21

no polar pneumonic

Answer 21

GAVLIMP

Question 22

polar pneumonic

Answer 22

STAGC

Question 23

+ charge

Answer 23

HAL