Sestini S, Ceccuzzi M L, Ricci C
Boll Soc Ital Biol Sper. 1980 Jun 30;56(12):1287-90.
In order to value the availability of niacin in man, it has been more suitable to test erythrocyte nicotinate-phosphoribosyltransferase and nicotinamide-phosphoribosyltransferase activities. These enzymes catalyze the production of Des-NMN and NMN from free bases. The radioactive compounds, produced from [14C] NAc and [14C] NAm, are isolated by a gel chromatography and counted in liquid scintillation. It has been observed that nicotinamide-phoshoribosyltransferase is scarcely active in human erythrocytes, while the nicotinate-phosphoribosyltransferase gives a good indication of niacin availability.
为了评估人体中烟酸的可利用性，检测红细胞烟酸磷酸核糖基转移酶和烟酰胺磷酸核糖基转移酶的活性更为合适。这些酶催化从游离碱产生脱辅基烟酰胺单核苷酸（Des-NMN）和烟酰胺单核苷酸（NMN）。由[14C]烟酰胺（NAc）和[14C]烟碱酰胺（NAm）产生的放射性化合物通过凝胶色谱法分离，并在液体闪烁仪中计数。据观察，烟酰胺磷酸核糖基转移酶在人红细胞中几乎没有活性，而烟酸磷酸核糖基转移酶能很好地指示烟酸的可利用性。
