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OKACHI, Ryo

doi:10.1271/nogeikagaku1924.53.12_r169

Cited by 8 publications

(1 citation statement)

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“…CVandamme and Voets, 1974;Vandamme, 1977;Okachi, 1979~. From thermodynamic considerations alone, any catalyst which hydrolyses an amide and an ester of a given acid by the mechanism shown in Fig. i, must also catalyze the acylation of the amine by the ester~ likewise, a catalyst effective as an esterase and acyl transferase must possess some degree of amidolytic activity.…”

Section: General Considerationsmentioning

confidence: 99%

Penicillin acylases as amidohydrolases and acyl transfer catalysts

Konecny

1981

Biotechnol Lett

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The hypothesis that an acyl-enzyme intermediate of the esterases from Xanthomonas cirri and Acetobacter turbidans is responsible for the acylation of 7-aminodeacetoxycephalosporanic acid and similar compounds by esters of amino acids, recently proposed by Kate, also accounts for the kinetics of hydrolysis of penicillin G by the amidohydrolase from E. coli and other reactions of the enzyme. Some further implications of the mechanism are derived and discussed. In recent studies concerning the acylation of 7-aminodeacetoxycephalosporanic acid (7-ADCA) by the methyl ester of D-phenyl glycine and of similar acylations catalyzed by the esterases from x. cirri and A. turbidans (Kato and coworkers 1980a, 1980b; Kate, 1980) it has been deduced that the reactions proceed via an acy!-enzyme intermediate. Kinetics of the reactions indicate a rate determining acylation of the enzyme by the ester, followed by a fast transfer of the acyl radical to the amino group of 7-ADCA or water, which compete for the acyl group as accepters. The purpose of this communication is to show that this mechanism has broader implications. In particular it accounts for * qhis paper is dedicated to Prof. G. Manecke, a pioneer of immobilized enzyme technology, with oongratulations to his 65thbirthday. 107

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Section: General Considerationsmentioning

confidence: 99%

Penicillin acylases as amidohydrolases and acyl transfer catalysts

Konecny

1981

Biotechnol Lett

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Kinetics and mechanism of acyl transfer by penicillin acylases

Konecny

Schneider

Sieber

1983

Biotech & Bioengineering

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The hypothesis that at least some penicillin acylases react via an acyl-enzyme intermediate was tested by kinetic investigations involving the methyl ester of cyanoacetic acid as the acyl donor, deacetyl-7-aminocephalosporanic acid as the acyl receptor, and penicillin acylase (E.C.3.5.1.11) from B. megaterium ATCC 14945 as the catalyst. The results obtained at low concentrations of the acyl receptor are in accord with the derived rate equations. Deviations observed at higher concentrations of the acyl receptor are discussed together with some practical implications of the mechanism.

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