一些硫醇酯水解反应作为木瓜蛋白酶催化水解脱酰基步骤模型的研究

Biochem J. 1965 Jul;96(1):194-8. doi: 10.1042/bj0960194.

The self-catalysed hydrolyses of the thiol esters, S-hippurylthioglycollic acid and S-ethyl monothiolsuccinate, have been shown to be slower than the deacylation step for the papain-catalysed hydrolysis of hippuric esters, by a factor approx. 10(5). This difference in rate constants largely reflects a difference in activation energy, which together with other evidence drawn from the literature make it unlikely that a carboxylate ion could be the nucleophile responsible for the deacylation of acyl-papain. 2. The imidazole-catalysed hydrolysis of S-hippurylthioglycollic acid and ethyl thiolacetate have activation energies similar to that for the deacylation step in papain-catalysed hydrolyses. This, together with other evidence drawn from the literature, suggests that the imidazole of a histidine residue is the nucleophile responsible for the deacylation of acyl-papain.

巯基酯、S-马尿酸硫代乙醇酸和S-乙基单硫代琥珀酸的自催化水解已被证明比木瓜蛋白酶催化马尿酸酯水解的脱酰步骤慢约10⁵倍。速率常数的这种差异在很大程度上反映了活化能的差异，这与文献中得出的其他证据一起，使得羧酸根离子不太可能是负责酰基木瓜蛋白酶脱酰的亲核试剂。2. S-马尿酸硫代乙醇酸和硫代乙酸乙酯的咪唑催化水解的活化能与木瓜蛋白酶催化水解的脱酰步骤相似。这与文献中得出的其他证据一起表明，组氨酸残基的咪唑是负责酰基木瓜蛋白酶脱酰的亲核试剂。

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核心技术专利：CN118964589B侵权必究

Biochem J. 1965 Jul;96(1):194-8. doi: 10.1042/bj0960194.

The self-catalysed hydrolyses of the thiol esters, S-hippurylthioglycollic acid and S-ethyl monothiolsuccinate, have been shown to be slower than the deacylation step for the papain-catalysed hydrolysis of hippuric esters, by a factor approx. 10(5). This difference in rate constants largely reflects a difference in activation energy, which together with other evidence drawn from the literature make it unlikely that a carboxylate ion could be the nucleophile responsible for the deacylation of acyl-papain. 2. The imidazole-catalysed hydrolysis of S-hippurylthioglycollic acid and ethyl thiolacetate have activation energies similar to that for the deacylation step in papain-catalysed hydrolyses. This, together with other evidence drawn from the literature, suggests that the imidazole of a histidine residue is the nucleophile responsible for the deacylation of acyl-papain.

巯基酯、S-马尿酸硫代乙醇酸和S-乙基单硫代琥珀酸的自催化水解已被证明比木瓜蛋白酶催化马尿酸酯水解的脱酰步骤慢约10⁵倍。速率常数的这种差异在很大程度上反映了活化能的差异，这与文献中得出的其他证据一起，使得羧酸根离子不太可能是负责酰基木瓜蛋白酶脱酰的亲核试剂。2. S-马尿酸硫代乙醇酸和硫代乙酸乙酯的咪唑催化水解的活化能与木瓜蛋白酶催化水解的脱酰步骤相似。这与文献中得出的其他证据一起表明，组氨酸残基的咪唑是负责酰基木瓜蛋白酶脱酰的亲核试剂。