Chymotrypsin Mechanism and Oxygen-Binding Proteins

Flashcards covering key concepts related to the chymotrypsin mechanism and the properties of hemoglobin and myoglobin.

The nucleophile that forms the acyl-enzyme intermediate is __.

Ser-195

With which the substrate and amino acid form a ___

Tetrahedral intermediate

The residue that exhibits electronic stabilization for His57 in the catalytic triad is __.

Asp 102

Chymotrypsin preferentially cleaves the side after ___amino acid side chains.

C-terminus; aromatic

The negative charge of the first tetrahedral intermediate is stabilized by the __

oxyanion hole

In which background ammonites provide a partial___ charge.

Positive

During the deacylation step, __ acts as the nucleophile.

water

His57 functions in __ catalysis throughout the chymotrypsin mechanism.

acid-base

The ___ of the substrate polypeptide leaves first, after the initial peptide bond cleavage.

N- terminus

A decrease in pH shifts Hb towards curve __.

Right

An increase in BPG shifts Hb towards curve __.

right

Mb reaches 88% fractional saturation with a pO2 of 20 torr. The dissociation constant (Kd) for Mb is __ torr.

2.7

What has a positive effect on hemoglobin?

Hint: Goes into R state, allows Ox to bind better

Carbon monoxide and oxygen

According to the Bohr effect, as the concentration of CO2 increases the concentration of H + __

Increases

What has a negative effect on hemoglobin?

Hint: Causes a loss of Ox/ Ox is released

2,3-BPG, carbon dioxide and hydrogen ions