Kitano H, Maeda Y, Furukawa K, Yamamoto T, Izumida R, Matsugo S
Department of Chemical and Biochemical Engineering, Toyama University, Japan.
Photochem Photobiol. 1995 Nov;62(5):809-12. doi: 10.1111/j.1751-1097.1995.tb09140.x.
Modification of an enzyme, alpha-chymotrypsin, was examined by using a water-soluble photo-Fenton reagent. By photoirradiation of the enzyme with the reagent, which can occupy a binding site of the enzyme, a tryptophan residue in the vicinity of the active site was oxidized to N-formylkynurenine. Concurrently, the catalytic properties of the enzyme were largely changed: the Km was increased and the kcat was decreased. The decrease in kcat for a specific amide substrate was the most significant among the esters and amides examined. The water-soluble photo-Fenton reagent would be useful to chemically modify relatively limited regions in biomolecules.
利用水溶性光芬顿试剂对α-糜蛋白酶进行了修饰研究。通过用该试剂对酶进行光照射，该试剂可占据酶的结合位点，活性位点附近的一个色氨酸残基被氧化为N-甲酰犬尿氨酸。同时，酶的催化特性发生了很大变化：米氏常数（Km）增加，催化常数（kcat）降低。在所研究的酯类和酰胺类底物中，特定酰胺底物的kcat降低最为显著。水溶性光芬顿试剂将有助于对生物分子中相对有限的区域进行化学修饰。
