Halkier B A, Scheller H V, Møller B L
Department of Plant Physiology, Royal Veterinary and Agricultural University, Frederiksberg, Denmark.
Ciba Found Symp. 1988;140:49-66. doi: 10.1002/9780470513712.ch5.
In vitro studies with a microsomal system obtained from etiolated sorghum seedlings have indicated a biosynthetic pathway for cyanogenic glucosides involving amino acids, N-hydroxyamino acids, aldoximes, nitriles and cyanohydrins. NADPH is an essential cofactor. Simultaneous measurements of tyrosine metabolism and oxygen consumption show that three molecules of oxygen are consumed for each molecule of p-hydroxymandelonitrile produced. This indicates the operation of three monooxygenases in the pathway and implies the involvement of one hitherto undetected intermediate in the pathway. The nature of this intermediate is unknown. Gel filtration and sucrose gradient centrifugation of the microsomal system resulted in a more than tenfold increase in specific activity. Attempts to further purify the system did not produce preparations of higher specific activity because of a simultaneous partial loss of essential components as demonstrated by reconstitution experiments.
利用从黄化高粱幼苗中获得的微粒体系统进行的体外研究表明，生氰糖苷的生物合成途径涉及氨基酸、N-羟基氨基酸、醛肟、腈和氰醇。NADPH是一种必需的辅助因子。酪氨酸代谢和耗氧量的同步测量表明，每产生一分子对羟基苯乙腈会消耗三分子氧气。这表明该途径中有三种单加氧酶起作用，意味着该途径中涉及一种迄今未检测到的中间体。这种中间体的性质尚不清楚。对微粒体系统进行凝胶过滤和蔗糖梯度离心后，比活性提高了十多倍。由于重组实验表明在进一步纯化系统的过程中必需成分会同时部分损失，因此未能得到比活性更高的制剂。
