Kølvraa S, Gregersen N
Biochem Med Metab Biol. 1986 Aug;36(1):98-105. doi: 10.1016/0885-4505(86)90112-x.
Prompted by the fact that the urinary excretion of organic acids in the riboflavin-deficient rat closely mimics that found in patients with inborn errors in the acyl-CoA dehydrogenation systems, the organelle localization and the apparent kinetic constants (Km and Vmax values) for the rat liver acyl-CoA:glycine-N-acyltransferase (glycine-N-acylase) toward isobutyryl-CoA, 2-methylbutyryl-CoA, isovaleryl-CoA, butyryl-CoA, hexanoyl-CoA, octanoyl-CoA, decanoyl-CoA, and benzoyl-CoA were determined. The studies on organelle localization demonstrated that the glycine-N-acylase is exclusively an intramitochondrial enzyme, and that no activity is present in peroxisomes, which also possess ability to produce Acyl-CoAs. The kinetic studies were done in order to elucidate whether the quantitative differences in excretion profile of acylglycines between riboflavin-deficient rats and patients with beta-oxidation defects are caused by differences in ability to conjugate the various acyl-CoAs. It was found that the Km values for the rat liver enzyme were generally somewhat lower than the values found in man, but with the same chain length profile. Consequently, the above-mentioned differences in excretion profile of acylglycines between riboflavin-deficient rats and patients with beta-oxidation defects cannot be explained by differences in affinity toward the glycine-N-acylase.
鉴于核黄素缺乏大鼠尿中有机酸的排泄情况与酰基辅酶A脱氢系统先天性缺陷患者的情况极为相似，我们测定了大鼠肝脏酰基辅酶A：甘氨酸 - N - 酰基转移酶（甘氨酸 - N - 酰基酶）对异丁酰辅酶A、2 - 甲基丁酰辅酶A、异戊酰辅酶A、丁酰辅酶A、己酰辅酶A、辛酰辅酶A、癸酰辅酶A和苯甲酰辅酶A的细胞器定位及表观动力学常数（Km和Vmax值）。细胞器定位研究表明，甘氨酸 - N - 酰基酶完全是一种线粒体内酶，而过氧化物酶体中没有活性，尽管过氧化物酶体也有产生酰基辅酶A的能力。进行动力学研究是为了阐明核黄素缺乏大鼠与β - 氧化缺陷患者之间酰基甘氨酸排泄谱的定量差异是否由结合各种酰基辅酶A能力的差异所致。结果发现，大鼠肝脏酶的Km值通常略低于人类的Km值，但链长分布相同。因此，核黄素缺乏大鼠与β - 氧化缺陷患者之间上述酰基甘氨酸排泄谱的差异不能用对甘氨酸 - N - 酰基酶亲和力的差异来解释。
