exam one cram notecards Flashcards
isolectric point and anion exchange
Pi>pH:protein is positively charged and will bind to cation exchange
pH>Pi: Protein is negativelt charged will bind to anion exchange
Ramachandran
Axis: X:psi, Y:phi
Gly: no restriction
Pro: restriction
Competitive inhibition
Binds to enzyme, changes slope and Km but not y int
multiply Km by alpha
uncompetitive inhibiton
binds to ES, same slope dif Y int and Km. a’/Vmax
noncompettivie
Both things,
a helix numbers
1.5 Angstroms/residue
3.6 residues per term
Cholera toxin symmetry
C5 symmetry
GroEL symmetry
C7
Where does trypsin cut? chemotrypsin?
Trypsin: Lys, Arg
Chemotryp: Try, trp, phe, leu
BOTH BLOCKED BY PROLINE
hemoglobin symmetry
C2
HIll coefficient
If hill>1=cooperative
if hill<1=not cooperative
bohr effect on hb
ph decrease, histidine protonated, salt bridge stronger, decrease O2 binding, more o2 to muscles. Shifts sigmoidal curve left
BPG
Shifts curve right
decreases HB affinity for O2, increases 02 delivery to tissue
RNase A mechanism
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
metal ion catalysis
Zinc coordinated by three histidines
zn polarizes H2O which ionizes bc the 4th histidine
OH nucleophillic attack on C of CO2
bicarbonate formed
