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The interplay of electrostatic fields and binding interactions determining catalytic-site reactivity in actinidin. A possible origin of differences in the behaviour of actinidin and papain.
1. The pH-dependence of the second-order rate constant (k) for the reaction of actinidin (EC with 2-(N'-acetyl-L-phenylalanylamino)ethyl 2'-pyridyl disulphide was determined and theExpand
Identification of signalling and non-signalling binding contributions to enzyme reactivity. Alternative combinations of binding interactions provide for change in transition-state geometry in
1. 2-(N'-Acetyl-L-phenylalanyl)hydroxyethyl 2'-pyridyl disulphide (compound V) was synthesized, and a study of the pH-dependence of the second-order rate constant (k) for its reaction with theExpand
Supracrystallographic resolution of interactions contributing to enzyme catalysis by use of natural structural variants and reactivity-probe kinetics.
1. The influence on the reactivities of the catalytic sites of papain (EC and actinidin ( of providing for interactions involving the S1-S2 intersubsite regions of the enzymes wasExpand
Consequences of molecular recognition in the S1-S2 intersubsite region of papain for catalytic-site chemistry. Change in pH-dependence characteristics and generation of an inverse solvent kinetic
1. The pH-dependences of the second-order rate constant (k) for the reactions of papain (EC with 2-(acetamido)ethyl 2'-pyridyl disulphide and with ethyl 2-pyridyl disulphide and of k forExpand
Substrate-derived two-protonic-state electrophiles as sensitive kinetic specificity probes for cysteine proteinases. Activation of 2-pyridyl disulphides by hydrogen-bonding.
1. 2-(N'-Acetyl-L-phenylalanylamino)ethyl 2'-pyridyl disulphide [compound (III)] and 2-(acetamido)ethyl 2'-pyridyl disulphide [compound (IV)] were synthesized by acylation of the common intermediate,Expand
Evaluation of hydrogen-bonding and enantiomeric P2-S2 hydrophobic contacts in dynamic aspects of molecular recognition by papain.
1. 2-(N'-Acetyl-D-phenylalanyl)hydroxyethyl 2'-pyridyl disulphide (compound IV) (m.p. 59 degrees C; [alpha]D20 -6.6 degrees (c 1.2 in methanol)) was synthesized. 2. The results of a study of theExpand
Dependence of the P2-S2 stereochemical selectivity of papain on the nature of the catalytic-site chemistry. Quantification of selectivity in the catalysed hydrolysis of the enantiomeric
1. N-Acetyl-L-phenylalanylglycine 4-nitroanilide and its D-enantiomer were synthesized and characterized and used as substrates with which to evaluate stereochemical selectivity in papain (ECExpand
Variation in the P2-S2 stereochemical selectivity towards the enantiomeric N-acetylphenylalanylglycine 4-nitroanilides among the cysteine proteinases papain, ficin and actinidin.
1. Values of the kinetic specificity constant, kcat./Km, for the hydrolysis of N-acetyl-L-phenylalanylglycine 4-nitroanilide (I) and of its D-enantiomer (II) catalysed by ficin (EC and byExpand