TY  - JOUR
PY  - 1993//
TI  - Mechanism-based catalytic antibody inactivation
JO  - Biochemical and biophysical research communications
A1  - Angeles, T. S.
A1  - Martin, M. T.
SP  - 696
EP  - 701
VL  - 197
IS  - 2
N2  - Studies of alternative substrates of the catalytic monoclonal antibodies 18H4, 7D4, and 45A11 provided us with a better understanding of the mechanism of ester hydrolysis employed by these isoabzymes. The antibodies were studied with analogs of the substrate, phenyl acetate; N-acetylglycine phenyl ester 3 and N-carbobenzoxy-glycine phenyl ester 4. All three antibodies catalyzed 3 hydrolysis with kinetic constants similar to those seen with phenyl acetate hydrolysis. However, 4 was found to be a mechanism-based (suicide) inactivator of 18H4 with a kinact of 0.29 min-1 and a K' of 64 microM. Antibody 18H4 was inactivated by 4 after 3.6 turnovers resulting in the acylation of 1.6 tyrosines per combining site. The data conform to a mechanism in which an inactive O-ZGly-tyrosyl-antibody is formed via a Michaelis complex.<p /> <p>Language: en</p>
LA  - en
SN  - 0006-291X
UR  - http://dx.doi.org/10.1006/bbrc.1993.2535
ID  - ref1
ER  -