Briske-Anderson M, Duerre J A
Can J Biochem. 1982 Feb;60(2):118-23. doi: 10.1139/o82-016.
The kinetic constants for the reversible adenosylhomocysteine hydrolase from rat liver have been determined. The Km values of the enzyme for S-adenosylhomocysteine, adenosine, and l-homocysteine were 12.3 micro M, 0.94 micro M, and 164 micro M, respectively. Under the specified conditions the Vmax for the synthetic reaction was 6.2 mumol/min per milligram, while the Vmax for the hydrolytic reaction was 0.72 mumol/min per milligram. l-Homocysteine acted as a mixed-type inhibitor of the hydrolytic reaction. Adenosine, a competitive inhibitor of both the synthetic and hydrolytic reactions (Ki = 1.2 +/- 0.2 micro M), was found to be a product of the reaction. In the absence of l-homocysteine about 0.8 nmol of adenosine was hydrolyzed to adenine and ribose per minute per milligram enzyme.
已测定大鼠肝脏中可逆性腺苷同型半胱氨酸水解酶的动力学常数。该酶对S-腺苷同型半胱氨酸、腺苷和L-同型半胱氨酸的Km值分别为12.3微摩尔、0.94微摩尔和164微摩尔。在特定条件下，合成反应的Vmax为每毫克6.2微摩尔/分钟，而水解反应的Vmax为每毫克0.72微摩尔/分钟。L-同型半胱氨酸作为水解反应的混合型抑制剂。腺苷是合成反应和水解反应的竞争性抑制剂（Ki = 1.2 +/- 0.2微摩尔），被发现是该反应的产物。在没有L-同型半胱氨酸的情况下，每毫克酶每分钟约有0.8纳摩尔的腺苷被水解为腺嘌呤和核糖。
