Determination of Serum Biotinidase Activity with Biotinyl Derivatives of lodotyramines as Substrates
作者:Stavros A. Evangelatos、Sotiris E. Kakabakos、Gregory P. Evangelatos、Dionyssis S. Ithakissios
DOI:10.1002/jps.2600821209
日期:1993.12
radioactive counterparts and used these substances as substrates to estimate serum biotinidase activity in a radioassay system. The Km values determined for mono- and di-iodobiotinyl derivatives were 15.8 and 25.9 microM, respectively, whereas, the maximum velocities of the enzymatic reaction were 27.0 and 8.7 nmol.min-1.mL-1, respectively. Both substrates competed with biocytin for the same active site
我们合成了生物素化的一碘和二碘吡啶胺及其放射性对应物,并使用这些物质作为底物来估计放射测定系统中的血清生物素酶活性。测定的单碘和二碘生物素衍生物的Km值分别为15.8和25.9 microM,而酶促反应的最大速度分别为27.0和8.7 nmol.min-1.mL-1。两种底物都与生物胞素竞争相同的酶活性位点,单碘和二碘化底物的Ki值分别为7.30和9.56 microM。使用[125I]生物素-单碘代乙胺作为底物可获得更高的测定灵敏度,并且所得值与采用公认的比色法测定的值直接相关(r = 0.9377,n = 31)。但是,对于常规使用,该测定可以通过用生物胞素而不是其“冷”对应物稀释放射性示踪剂来完成,因为它是可商购的试剂。在这种情况下获得的值也与通过比色测定法确定的值非常相关(r = 0.9289,n = 31)。