Lien L F, Beattie D S
Enzyme. 1982;28(2-3):120-32. doi: 10.1159/000459096.
Detailed procedures are given for the colorimetric assay of gamma-aminolevulinic acid synthase. The gamma-aminolevulinic acid formed is converted to a pyrrole with acetylacetone and quantitated spectrophotometrically at 552 nm after reaction with Ehrlich's reagent. Three methods, chromatography on Dowex-1, ether extraction and dichloromethane extraction, are compared for the isolation of the pyrrole. Extraction with ether was the preferred method and, when applied to either homogenates or mitochondria from rat liver, yielded values of 105 U (nmol/b)/g liver and 0.41 U/mg mitochondrial protein. The method is rapid, simple and inexpensive; however, its use is restricted to activities of 0.56 U/ml of incubation mixture or greater.
文中给出了γ-氨基乙酰丙酸合酶比色测定的详细步骤。生成的γ-氨基乙酰丙酸与乙酰丙酮反应转化为吡咯，再与埃利希试剂反应后于552nm处进行分光光度法定量。比较了三种分离吡咯的方法，即Dowex - 1柱色谱法、乙醚萃取法和二氯甲烷萃取法。乙醚萃取是首选方法，应用于大鼠肝脏匀浆或线粒体时，得到的值分别为105U（nmol/b）/g肝脏和0.41U/mg线粒体蛋白。该方法快速、简单且成本低；然而，其适用范围限于孵育混合物活性为0.56U/ml或更高的情况。
