The Interaction of Ethyl 1-Acetyl-2-benzylcarbazate with alpha-Chymotrypsin<sup>1</sup>

Kurtz, Abraham N.; Niemann, Carl

doi:10.1021/ja01469a024

Cited by 18 publications

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“…A considerable body of evidence supports this view. (1) Kurtz & Niemann (1961a) showed that the ethyl ester analogous to NPABC inhibits a-chymotrypsin almost competitively and is presumably bound at the active site. (2) Proflavine is bound by achymotrypsin in the pH range 4-0-7-6, but not if the enzyme is pretreated with L-1-chloro-3-toluenepsulphonamido -4 -phenylbutan -2 -one, phenylmethanesulphonyl fluoride or N-cinnamoylimidazole (Glazer, 1965;Bernhard, Lee & Tashjian, 1966).…”

Section: Discussionmentioning

confidence: 99%

“…The objectives and rationale of the present work were outlined in the introduction to the preceding paper (Elmore & Smyth, 1968). Although Nacetyl-L-phenylalanine ethyl ester is a good substrate for a-chymotrypsin, the nitrogen analogue ethyl N2-acetyl-Nl-benzylcarbazate is not hydrolysed by the enzyme (Kurtz & Niemann, 1961a). It does inhibit chymotrypsin, however, probably not quite competitively, but nearly so.…”

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confidence: 95%

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A new method for determining the absolute molarity of solutions of trypsin and chymotrypsin by using p-nitrophenyl N2-acetyl-N1-benzylcarbazate

Elmore

Smyth

1968

Biochemical Journal

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1. p-Nitrophenyl N(2)-acetyl-N(1)-benzylcarbazate (NPABC) was synthesized and shown to acylate alpha-chymotrypsin stoicheiometrically; reaction at 25 degrees occurs almost instantaneously at pH7.04 and within 2min. at pH5.04 and there is no observable turnover during 10min. 2. The absolute molarity of solutions of alpha-chymotrypsin can be determined by spectrophotometric measurement of the p-nitrophenol liberated during the acylation step; the results obtained at pH5.04 and pH7.04 agree with one another and with those determined by the method of Erlanger & Edel (1964). 3. Trypsin reacts stoicheiometrically, but more slowly than alpha-chymotrypsin, with NPABC, and it, like chymotrypsin, can be spectrophotometrically titrated at pH7.04. At pH5.04, however, reaction between trypsin and NPABC is sufficiently slow for the reagent to be nearly specific for alpha-chymotrypsin. Specificity for one or other enzyme can be ensured by using soya-bean trypsin inhibitor or the chymotrypsin inhibitor l-1-chloro-3-toluene-p-sulphonamido-4-phenylbutan-2-one. Bovine thrombin does not react with NPABC. 4. Evidence is presented that indicates that acylation of alpha-chymotrypsin and trypsin by NPABC occurs at the active centres of the enzymes. 5. Evidence was obtained that indicates that one or more tryptophan residues move into a more hydrophobic environment when alpha-chymotrypsin and trypsin are acylated by NPABC.

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Section: Discussionmentioning

confidence: 99%

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confidence: 95%

A new method for determining the absolute molarity of solutions of trypsin and chymotrypsin by using p-nitrophenyl N2-acetyl-N1-benzylcarbazate

Elmore

Smyth

1968

Biochemical Journal

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“…This makes azapeptides more resistant to enzymatic hydrolysis than their normal peptide analogues. The reduced reactivity of the carbonyl group also makes azapeptides with poor leaving groups poor inhibitors of serine proteases [119,[120][121][122][123]. However, due to the greater nucleophilicity of the thiolate at the active site of cysteine proteases, these enzymes including calpain are inhibited by azapeptides [124].…”

Section: Sar Of the Address Region Of Calpain Inhibitorsmentioning

confidence: 99%

A Survey of Calpain Inhibitors

Donkor¹

2000

CMC

136

153

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Calpain is unique among the cysteine protease family of enzymes in that it combines thiol protease activity with calmodulin-like activity. Despite its wide spread distribution the exact physiological function(s) of calpain is yet to be deciphered. The enzyme is however, implicated in a number of pathophysiological conditions. Due to the potential of calpain as a therapeutic target a number of inhibitors have been described for the enzyme. In this article we have grouped calpain inhibitors into those derived from natural sources, and those derived from chemical synthesis. Additionally, an overview of functional groups that have been used as warheads of calpain inhibitors is presented along with a discussion of the structure activity relationship studies of the address region of peptidyl calpain inhibitors. Recent work in this area has led to a better understanding of the structural requirements for tight binding of inhibitors to the active site of calpain. A discussion of peptidomimetic calpain inhibitors, nonpeptide calpain inhibitors, and selectivity of some calpain inhibitors are also presented. The recent disclosure of the crystal structure of a nonpeptide calpain inhibitor bound to a hydrophobic pocket on the calcium-binding domain of calpain has opened the door to future development of potent cell permeable nonpeptide calpain inhibitors.

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“…Kurtz and Nieman were the first to study the reaction of an azaamino acid derivative with a protease and showed that Ac-APhe-OEt was a weak, reversible (competitive) inhibitor of chymotrypsin (K i = 20 mM) [61]. Elmor and Smyth thought that an aryl ester might be reactive enough to acylate the enzyme, so they synthesised the nitrophenyl analogue , Ac-APhe-ONp, which acylates chymotrypsin stoichiometrically and can be used as an active site titrant to determine the absolute molarity of active chymotrypsin in solution [57,[62][63][64][65].…”

Section: Protease Inhibitors and Active Site Titrantsmentioning

confidence: 99%

Azapeptides as Pharmacological Agents

Zega¹

2005

Current Medicinal Chemistry

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Azapeptides, formed by replacing the C α of amino acid residues by nitrogen, are promising peptidomimetic compounds. Azaamino acids impart a unique conformational property to peptide structures because of the loss of chirality and reduction of flexibility of the parent linear peptide. The peculiar conformational properties make azaamino acids an attractive tool for drug design involving specific secondary structures in peptides and proteins. Additionally, since azapeptides are less susceptible to enzymatic breakdown by proteases, they may possibly lead to orally active drugs with longer duration of action. One of the advantages of azapeptides is their unproblematic synthesis allowing retention of the amino acid side chain. Azapeptides have been developed by several groups for the design of hormone analogues, protease inhibitors and active site titrants.

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The Interaction of Ethyl 1-Acetyl-2-benzylcarbazate with alpha-Chymotrypsin¹

Cited by 18 publications

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A new method for determining the absolute molarity of solutions of trypsin and chymotrypsin by using p-nitrophenyl N2-acetyl-N1-benzylcarbazate

A new method for determining the absolute molarity of solutions of trypsin and chymotrypsin by using p-nitrophenyl N2-acetyl-N1-benzylcarbazate

A Survey of Calpain Inhibitors

Azapeptides as Pharmacological Agents

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The Interaction of Ethyl 1-Acetyl-2-benzylcarbazate with alpha-Chymotrypsin1

Cited by 18 publications

References 0 publications

A new method for determining the absolute molarity of solutions of trypsin and chymotrypsin by using p-nitrophenyl N2-acetyl-N1-benzylcarbazate

A new method for determining the absolute molarity of solutions of trypsin and chymotrypsin by using p-nitrophenyl N2-acetyl-N1-benzylcarbazate

A Survey of Calpain Inhibitors

Azapeptides as Pharmacological Agents

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Product

Resources

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The Interaction of Ethyl 1-Acetyl-2-benzylcarbazate with alpha-Chymotrypsin¹