Pember S O, Johnson K A, Villafranca J J, Benkovic S J
Department of Chemistry, Pennsylvania State University, University Park 16802.
Biochemistry. 1989 Mar 7;28(5):2124-30. doi: 10.1021/bi00431a024.
Steady-state kinetic analysis of pterin-dependent phenylalanine hydroxylase from Chromobacterium violaceum indicated that the enzyme follows a partially ordered reaction mechanism. The data suggested that oxygen is the first substrate to bind to the enzyme. This result was further supported by rapid-quench experiments in which the enzyme-oxygen complex was trapped to yield product. Additional support for the presence of an enzyme-oxygen complex was derived from magnetic susceptibility measurements of molecular oxygen in the presence and absence of cuprous phenylalanine hydroxylase. The magnetic susceptibility of dissolved oxygen decreased in the presence of the enzyme, supporting a direct oxygen-metal interaction.
对来自紫色色杆菌的蝶呤依赖性苯丙氨酸羟化酶进行的稳态动力学分析表明，该酶遵循部分有序的反应机制。数据表明，氧气是第一个与该酶结合的底物。快速淬灭实验进一步支持了这一结果，在该实验中，酶 - 氧气复合物被捕获以产生产物。对酶 - 氧气复合物存在的额外支持来自于在有无亚铜苯丙氨酸羟化酶的情况下对分子氧的磁化率测量。在酶存在的情况下，溶解氧的磁化率降低，这支持了氧与金属的直接相互作用。
