Studies on the Active Site of Papain. I. Inhibition by Barbituric Acid Derivatives with Active Methylene Group and Active Imide Group

Mechanism-Based Studies of the Active Site-Directed Inhibition and Activation of Enzyme Transketolase

Derivatives of phenyl-keto butenoic acids have been reported to be inhibitors of pyruvate decarboxylase, (PDC). The inhibition of transketolase, a thiamine requiring enzyme such as PDF, by meta nitrophenyl derivative of 2-oxo-3-butenoic acid (MNPB) is reported here. These studies indicate that the inhibitor binds to the enzyme at the active site. A two-step inhibition was observed, first th...

Fluorescence energy transfer studies on the active site of papain.

Measurements have been performed of the excited-state lifetimes and fluorescence yields of papain tryptophan units when acyl derivatives of Phe-glycinal are bound at the active site of the enzyme. The enhancement of tryptophan fluorescence in complexes of papain with the acetyl or benzyloxycarbonyl derivatives is not stereospecific with respect to the configuration of the phenylalanyl residue, ...

Studies on the active--SH group of papain and on the mechanism of papain activation by thiols.

It is now generally agreed that papain possesses a single reactive sulfhydryl group which is essential for activity and which probably participates in the catalytic mechanism by forming acyl intermediates with the different substrates (2, 3). Smith (4) has claimed that the essential sulfhydryl group of papain is kinetically more active than most protein sulfhydryl groups and that it possesses d...

PROBING THE ACTIVE SITE OF RHODANESE WITH DISULFIDE REAGENTS

mechanism-based studies of the active site-directed inhibition and activation of enzyme transketolase

derivatives of phenyl-keto butenoic acids have been reported to be inhibitors of pyruvate decarboxylase, (pdc). the inhibition of transketolase, a thiamine requiring enzyme such as pdf, by meta nitrophenyl derivative of 2-oxo-3-butenoic acid (mnpb) is reported here. these studies indicate that the inhibitor binds to the enzyme at the active site. a two-step inhibition was observed, first the in...