[肝脏和脑豚鼠鸟嘌呤氨基水解酶（作者译）]

[Liver and brain guinea-pig guanine aminohydrolase (author's transl)].

作者信息

Martínez-Farnos L, Gubert S, Bozal J

出版信息

Rev Esp Fisiol. 1978 Jun;34(2):205-12.

Abstract

Guinea-pig brain guanine aminohydrolase (E.C. 3.5.4.3) (M = 120,000 +/- 5,000 daltons) only exhibited one active electrophoretic band; its mobility is similar with that observed for the guinea-pig liver molecular form III. Both forms appear to have coincident activity with pH, as well as an analogous thermal stability and Km values with different substrates showing a different behaviour with the molecular form I of guinea-pig liver enzyme. Brain guanine aminohydrolase and liver molecular form III have similar pK'a values suggesting the participation of histidine and cysteine (-SH) in the enzymatic catalysis. The competitive inhibition by p-chloromercuribenzoate may corroborate the intervention of the last-one.

摘要

豚鼠脑鸟嘌呤氨基水解酶（E.C. 3.5.4.3）（分子量 = 120,000 ± 5,000道尔顿）仅显示出一条活性电泳带；其迁移率与豚鼠肝分子形式III所观察到的相似。两种形式在pH值方面似乎具有一致的活性，以及类似的热稳定性和针对不同底物的Km值，不过与豚鼠肝酶的分子形式I表现出不同的行为。脑鸟嘌呤氨基水解酶和肝分子形式III具有相似的pK'a值，表明组氨酸和半胱氨酸（-SH）参与酶催化作用。对氯汞苯甲酸的竞争性抑制可能证实了后者的参与。