^(35)S标记L型胱氨酸的生物合成

PREPARATION OF ^(35)S-LABELLED LCYSTINE BY BIOSYNTHESIS

一、前言^(35)S标记L型胱氨酸是研究蛋白质代谢的重要示踪剂之一。制取^(35)S记标记L型胱氨酸产品,以生物材料酵母微生物为原料,此酵母在含有无载体Na_2^(35)SO_4的培养基内培养,在通气的情况下,孵育48h。

A modified method for the biosynthesis of L-cyctine-^(35)S from baker's yeast(Saccharomyces Cerevisiae) is described. The yeast was cultivated in a sulphur-depleted medium containing carrier-free Na_2 ^(35)SO_4 under bubbling of air during 48hours, yeast proteins were hydrolysed enzymatically into aminoacids, and L-cystine-^(35)S was isolated by ion exchange chromatography on a column. Radioactive yieldfor L-cystine-^(35)S is 16-19% and the obtained products have specific activities of 15-22 mCi/mmol and radiochemical purity better than 95%.