Tasaka Y, Marumo K, Inoue Y, Hirata Y
Diabetes Center, Tokyo Women's Medical College, Japan.
Endocrinol Jpn. 1989 Feb;36(1):47-53. doi: 10.1507/endocrj1954.36.47.
The acid saline extract (ASE) of rat submaxillary gland exerts a powerful degrading effect on 125I-glucagon. In order to study the degradation of other 125I-peptides by ASE and the effects of their inhibitors, 125I-pancreatic polypeptide (PP) and 125I-insulin were used together with 125I-glucagon. The degradation studies were done by the trichloroacetic acid (TCA) method or gel filtration. Besides 125I-glucagon, 125I-PP was found to be destroyed by ASE in the ordinary immunoassay system using the TCA method, but 125I-insulin was intact in the presence of ASE. Leupeptin, and to a lesser extent p-chloromercuriphenyl-sulfonic acid (PCMS) and N-ethylmaleimide, inhibited the destruction of 125I-glucagon or -PP under the TCA method. PCMS was especially protective at high concentrations, for example 16 mM. These findings were confirmed by gel filtration of the assay mixture. In the presence of leupeptin (0.4 mM) and PCMS (16 mM), no shift in the peak of labelled glucagon or PP occurred. Thus ASE degrades not only 125I-glucagon but -PP, and thiol proteinase inhibitors have a strong inhibitory action on them.
大鼠颌下腺的酸性盐提取物（ASE）对125I-胰高血糖素具有强大的降解作用。为了研究ASE对其他125I-肽的降解作用及其抑制剂的影响，将125I-胰多肽（PP）和125I-胰岛素与125I-胰高血糖素一起使用。降解研究通过三氯乙酸（TCA）法或凝胶过滤进行。除125I-胰高血糖素外，在使用TCA法的普通免疫分析系统中，发现125I-PP被ASE破坏，但在有ASE存在的情况下125I-胰岛素保持完整。亮抑酶肽以及在较小程度上对氯汞苯磺酸（PCMS）和N-乙基马来酰亚胺抑制了TCA法下125I-胰高血糖素或-PP的破坏。PCMS在高浓度（例如16 mM）时具有特别的保护作用。通过对分析混合物进行凝胶过滤证实了这些发现。在亮抑酶肽（0.4 mM）和PCMS（16 mM）存在的情况下，标记的胰高血糖素或PP的峰没有发生位移。因此，ASE不仅降解125I-胰高血糖素，还降解-PP，并且巯基蛋白酶抑制剂对它们具有强烈的抑制作用。
