Enzymology: rate constants

Selected entries from Methods in Enzymology [vol, page(s)] Types of organophosphorus inhibitors, 11,686-688 toxicity hazards, 11,688 purity and analysis, 11,688 solutions of organophosphorus compounds, 11,689 estimation of specific radioactivity of organophosphorus compounds, 11,689-690 method for estimating phosphorus content, 11,691 reactions with enzymes, 11,691 -701 [rate constants, 11,692 phosphorylation of chymotrypsin, 11, 694-696 identification of phosphoryl and phosphonyl peptides,... 

Selected entries from Methods in Enzymology [vol, page(s)] Sulfonylation reaction, 11, 706 reaction kinetics, 11, 707 second-order rate constants for inactivation of chymotrypsin, trypsin, and acetylcholine esterase by PMSE and related sulfonylat-ing agents, 11, 707 reactivation of PMS-chymotrypsin, 11, 710 as inhibitor [of calcium-activated factor, 80, 674 of cathepsin G, 80, 565 of crayfish trypsin, 80, 639 of elastase, 80, 587 of pro-lylcarboxypeptidase, 80, 465 of protease Re, 80, 691 of protease So, 80, 695 of protein C, 80, 329] proteolysis, 76, 7. 

What can we learn about mechanism from protein engineering that cannot be learned from classical enzymology Chapter 7 begins with the statement The mechanism of an enzymatic reaction is ultimately defined when all the intermediates, complexes, and conformational states of an enzyme are characterized and the rate constants for their interconversion are determined. The classical delineation of a mechanism would have been achieved when the general nature of intermediates on a pathway and the type of catalysis had been determined. But... 

Breslow and co-workers have studied the mechanism of imidazole-catalyzed hydrolysis of both cyclic phosphate esters and of RNA (67-72). These studies are directed toward a more detailed understanding of the mechanism of the hydrolysis of RNA catalyzed by ribonuclease A (RNase A). In particular, recent studies by Breslow and co-workers have addressed the interesting and enzymologically pertinent question of the origin of the bell-shaped dependence of hydrolytic rate constant on pH in both enzymic and nonenzymic reactions. 

Michaelis-Menton equation/kinetics This equation, which is central to enzymology, describes the relationship between the initial rate of reaction (v) and the substrate concentration (Q. It gives the initial rate of reaction as v = V ax C/(K +C) where V ax is the maximum velocity of reaction, C is the concentration of substrate and is the Michaelis-Menton constant. C is equal to the Michaelis-Menton constant when vis 50% of micro- A prefix meaning small. 

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