Zimmermann R, Sagstetter M, Schlenstedt G
Institut für Physiologische Chemie der Universität München, FRG.
Biochimie. 1990 Feb-Mar;72(2-3):95-101. doi: 10.1016/0300-9084(90)90134-3.
Import of the small precursor protein preprocecropin A (ppcec A) into dog pancreas microsomes under post-translational conditions does not involve the ribonucleoparticles, signal recognition particle and ribosome, and their receptors on the microsomal surface, docking protein and ribosome receptor. In this study, we attempted to obtain direct evidence for the involvement of proteinaceous membrane components in this alternative import mechanism by utilizing various sulfhydryl-modifying reagents (N-ethylmaleimide (NEM), N-iodoacetylaminoethyl-5-naphthylamine-1- sulphonic acid (AEDANS) and iodoacetamide (IAA]. As a result of observing the inhibitory effect of 2 reagents (NEM and AEDANS) on the microsomes with respect to ppcec A-import, we concluded that there is at least one membrane protein with a cytoplasmically exposed sulfhydryl involved in ppcep A-import. This membrane protein(s) is (are) distinct from membrane proteins which are known to be involved in protein import, such as the signal peptidase and the so-called signal sequence receptor.
在翻译后条件下，将小前体蛋白前原杀菌肽A（ppcec A）导入犬胰腺微粒体并不涉及核糖核蛋白颗粒、信号识别颗粒和核糖体，以及它们在微粒体表面的受体、对接蛋白和核糖体受体。在本研究中，我们试图通过使用各种巯基修饰试剂（N-乙基马来酰亚胺（NEM）、N-碘乙酰氨基乙基-5-萘胺-1-磺酸（AEDANS）和碘乙酰胺（IAA））来获得蛋白质膜成分参与这种替代导入机制的直接证据。通过观察2种试剂（NEM和AEDANS）对微粒体ppcec A导入的抑制作用，我们得出结论，至少有一种具有细胞质暴露巯基的膜蛋白参与了ppcep A的导入。这种膜蛋白与已知参与蛋白质导入的膜蛋白不同，如信号肽酶和所谓的信号序列受体。
