δ-(L-α-Amino[1,1,6-17O/18O]-adipyl)-L-cysteiny-D-valine was converted into isopenicillin N in cell-free extracts of Cephalosporium acremonium with no loss of 17O/18O label as shown by 17O n.m.r. spectroscopy and mass spectrometry; incubation of unlabelled tripeptide in cell-free system containing 17O/18O-enriched water produced isopenicillin N with no incorporation of 17O/18O.
δ-(L-δ-
氨基[1,1,6-17O/18O]-己二基)-
L-半胱氨酸-
D-缬氨酸在无细胞
头孢菌素提取物中转化为异
青霉素 N,17O n. 显示 17O/18O 标记没有损失。m.r. 光谱法和质谱法;在含有 17O/18O 富集
水的无
细胞系统中培养未标记的三肽,产生异
青霉素 N,但没有 17O/18O 的掺入。