Kinetics of Beef Heart Glutamic-alanine Transaminase.
نویسندگان
چکیده
It has now been clearly established that pyridoxal phosphate serves as the coenayme of many transaminases. Several lines of evidence have indicated that the coenzyme acts alternately as acceptor and donar of amino groups, shuttling between the aldehydic (pyridoxal phosphate) and amino (pyridoxamine phosphate) forms (2-11). However, a detailed study of the kinetics of the transaminase reaction which might corroborate this concept has been lacking. A kinetic treatment of such shuttle or “ping-pong” mechanisms has been provided by Cleland (12). With this aim in mind, glutamic-alanine transaminase (L alanine : 2 oxoglutarate aminotransferase, EC 2.6.1.2) was isolated and highly purified from beef heart, and a study of its kinetics was undertaken. While this work was in progress, Velick and Vavra (8) reported on thti kinetics of glutamic-aspartic transaminase (L asparate : 2 oxoglutarate aminot,ransferase, EC 2.6.1.1) isolated from pig heart, and Hopper and Segal (13) described some kinetic properties of glutamic-alanine transaminase, isolated from rat liver. The results obtained in both laboratories support the proposed shuttle mechanism as do the kinetic studies on beef heart glutamic-alanine transaminase reported herein.
منابع مشابه
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ورودعنوان ژورنال:
- The Journal of biological chemistry
دوره 240 شماره
صفحات -
تاریخ انتشار 1965