Download Exercise 3

Chem 256 Exercise 3
Names ________________________________
Due Tuesday March 10
Transaminases using PLP
NH3+
CH3
CO2-
alanine
-
+
CO2-
O2C
O
ketoglutarate
-
O
transaminase
CH3
CO2-
O2C
CO2-
+
keto acid (pyruvate)
NH3+
glutamate
The transamination reaction above requires the coenzyme pyridoxal-5-phospate (PLP) to carry out the
amino group transfer from alanine to ketoglutarate to form Glutamate and pyruvate. Your text on pg
721 shows the mechanism for stage I of this reaction; the transformation of the amino acid to the keto
acid (we also did this in lecture).
A Draw the arrow pushing mechanism for stage II of this reaction which transforms a-Ketoglutarate to
glutamate. Be sure to use an arrow pushing mechanism as done on pg 721 of Voet.
B What is the fate of the glutamate product in this reaction?