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lin suan an ji mei de yan jiu . lin suan an ji mei dui yu lin zuo an lei hua he wu de huo li
Pages: 142-149
Year: Issue:  2
Journal: Acta Physiologica Sinica

Keyword:  氨基酶焦磷酸胺化合物酰胺类化合物酶活力提取液底物磷酸肌酸磷化合物苯甲胺;
Abstract: The stability of synthetic phosphoramides of aniline,p-chloroaniline,p-amino- benzoic acid,o-methoxyaniline sulfanilamide and benzylamine has been tested separately in acid and alkaline(pH 5.0 and pH 9.0)solutions.It was found that all these compounds are hydrolyzed in different degrees;among which N-(p-chlorophenyl)amidophosphoric acid is the most stable.This compound was thus used as substrate for most enzyme studies in spite of its low solubility.Phosphoramides of p-aminobenzoic acid and benzylamine are unsuitable as substrates,due to their instability in solution in which the enzyme activity is measured. The phosphoamidase aetivity of the purified enzyme preparation from ox spleen on the phos- phoramide compounds is higher at pH 5.0 than at pH 9.0.The rate of hydrolysis and the affinity of the enzyme with the substrate are different for different phosphoramides.It is therefore evident that phosphoamidase activity is closely related to the structure of the substrate. Among the splitting products of phosphoramides,amines have little effect on the enzyme activity,while phosphate ion has quite significant inhibitory effect. From the experiments on the enzyme activity of rat tissue ertracts,it is seen that: (1)The ratio.of the activities on substrates with similar structures is parallel in all tissues, but different in substrates with different structures,indicating that there may exist more than one phosphoamidases. (2)The content of phosphoamidase in the various tissues of the rat varies to a considerable extent.Spleen has the highest phosphoamidase content. (3)Muscle-tissue extract contains a considerable amount of phosphoamidase activity upon synthetic compounds containing P-N linkage.It would appear that phosphocreatine,which is rich in muscle,might be the natural substrate for this enzyme.
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