[FROM THE WILLIAMH. NICHOLS LABORATORY, NEWYORKUNIVERSITY, AND THE DEPARTMENT OF BIOLOGICAL CHEMISTRY, COLLEGE OF PHYSICIANS AND SURGEONS, COLUMBIA UNIVERSITY ]
THE TRANSAMINATION REACTION. THE MECHANISM O F THE REACTION BETWEEN alpha KETO ACIDS AND alpha AMINO ilCIDS ROBERT M. HERBST*
AND
D. RITTENBERG
Received June 4, 194.3
Several years ago one of us described a reaction in which an alpha keto acid was aminated and reduced to the corresponding amino acid a t the expense of another amino acid (1). Subsequently, on the basis of a study of an extensive series of reactions, the following mechanism was proposed (2). R-CH-NHz
I
COOH (A)
+
O=C-R’
-HzO,
I
R-CH-N=C-R’
I
COOH
(B)
-COz
1
I l-coi
R-CH=N-CH-R’
I
I
COOH
COOH
/+HZ 0
I
COOH
1
R-CH-N=CH-R’
R-CH-NHz
I
; COOH
pH2
+ R’CHO
RCHO
COOH
0
+ HzN-CH-R’ I
COOH
Soon thereafter an analogous reaction, catalyzed by enzyme systems of certain animal tissues, was described by Braunstein and Kritzmann (3) who introduced describe such reactions, the term Umaminierung-transamination-to It has been suggested (2) that the process of decarboxylation involved in the above mechanism was intimately associated with the shift of the double bond in system. At that time few data were the methyleneazomethine ( fC-N=C
