A quantitative analysis of the binding of N-acyl derivatives of alpha-aminoamides by alpha-chymotrypsin.

Hamilton, C. L.; Niemann, Carl; Hammond, George S.

doi:10.1073/pnas.55.3.664

Cited by 18 publications

(6 citation statements)

References 7 publications

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“…The remaining question, whether pH-dependent productive binding or pH-dependent nonproductive binding is responsible for the pH-Ais effects observed with anilides, is still open. The determinant formulation of Hamilton et al (1966) has been used in an attempt to resolve this question. There is, however, some question whether the empirical microscopic binding terms derived by Hamilton et al for unsubstituted amides of iV-acylamino acids are valid for anilide substrates and inhibitors.…”

Section: Discussionmentioning

confidence: 99%

“…Until the procedure of Hamilton et al is used in a complete sense, including the calculation of microscopic binding constants for anilides, it is apparent that the method cannot be relied upon to provide an unambiguous answer to the problem of nonproductive binding. Considering the cautions, which Hamilton et al (1966) discuss in the use of calculations of this type, it might appear that another method, such as crystal structure determinations, might be a more appropriate way of studying this problem (Robertus et al, 1972).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Binding rates, oxygen-sulfur substitution effects, and the pH dependence of chymotrypsin reactions

Hirohara¹,

Philipp²,

Bender³

1977

Biochemistry

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The pH dependence for acylation of alpha-chymotrypsin by N-acetyltryptophan p-nitrophenyl-, p-nitrothiophenyl-, ethyl-, and thiolethyl esters has been studied by the stopped-flow technique. Values for the acylation rate constant, k2, and the binding constant, KS, were obtained by using measurements of phenolate release, for the p-nitrophenyl esters, and proflavin displacement, for the ethyl esters. The oxygen esters tested have slightly higher k2 values, and substantially higher KS values relative to the analogous thiol esters. Whereas k2/KS for the thiolethyl ester is higher than that for the analogous oxygen ester, the k2/KS values for oxy- and thio-p-nitrophenyl esters are nearly identical. These data are interpreted to indicate rate-determining formation of a tetrahedral intermediate in acylation of alpha-chymotrypsin by p-nitrophenyl esters, and rate-determining breakdown of such an intermediate in the case of the ethyl esters. It is also concluded that the oxygen to sulfur substitution causes a substantial increase in the proportion of nonproductive binding in these substrates. pH dependent k2 and KS values were used to calculate values for k1 and k-1, the binding and debinding rate constants for the two p-nitrophenyl compounds. This is the first such calculation based on experimentally determined acylation rate constants.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Binding rates, oxygen-sulfur substitution effects, and the pH dependence of chymotrypsin reactions

Hirohara¹,

Philipp²,

Bender³

1977

Biochemistry

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“…It is a monomeric enzyme which shows no allosteric effects; the structural transitions which occur in the process of peptide bond cleavage are very small; and it can transfer acyl groups from a variety of donors, such as peptides or esters, to a variety of acceptors, such as water, alcohols, or amines. Comparisons among different donors and among different acceptors greatly facilitated the analysis of the individual catalytic steps (733,734).…”

Section: The Catalytic Mechanism Of Chymotrypsinmentioning

confidence: 99%

Principles of Protein Structure

Schulz¹,

Schirmer²

1979

Springer Advanced Texts in Chemistry

1,071

402

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“…Nonproductive binding provides a simple mechanism for the utilization of binding energy to bring about a decrease in the rate at which an enzyme catalyzes the reactions of poor substrates (25,(63)(64)(65)(66)(67). It is similar to the induced-fit mechanism in that it can be utilized to bring about specificity and that it does not facilitate the catalytic process per se.…”

Section: Nonproductive Bindingmentioning

confidence: 99%