Hasilik A, Tanner W
Antimicrob Agents Chemother. 1976 Sep;10(3):402-10. doi: 10.1128/AAC.10.3.402.
Carboxypeptidase Y from Saccharomyces cerevisiae contains 14% mannose, the only neutral sugar present. An antiserum can be raised in rabbits which reacts with both the protein and the sugar moieties of the enzyme. This antiserum also precipitates yeast invertase and yeast cell wall mannan. Thus carboxypeptidase Y, which is known to be localized in yeast vacuoles, is very probably a mannoprotein. Tunicamycin inhibits the apparent formation of carboxypeptidase Y to a similar extent as that of the externally localized mannoprotein, invertase. No accumulation of an inactive nonglycosylated or partly glycosylated carboxypeptidase Y occurs as determined by the immunoprecipitation technique. Tunicamycin also inhibits the apparent formation of proteinase A, whereas it does not affect the increase in the activities of a number of other enzymes. It is suggested that in the synthesis of glycoproteins there exists a regulatory link between the synthesis of their polypeptide chains and the reactions involved in their glycosylation.
来自酿酒酵母的羧肽酶Y含有14%的甘露糖，这是其唯一存在的中性糖。可以用兔子制备一种抗血清，它能与该酶的蛋白质和糖部分发生反应。这种抗血清还能沉淀酵母转化酶和酵母细胞壁甘露聚糖。因此，已知定位于酵母液泡中的羧肽酶Y很可能是一种甘露糖蛋白。衣霉素抑制羧肽酶Y的表观形成，其程度与外部定位的甘露糖蛋白转化酶相似。通过免疫沉淀技术测定，未出现无活性的非糖基化或部分糖基化羧肽酶Y的积累。衣霉素也抑制蛋白酶A的表观形成，而不影响其他多种酶活性的增加。有人提出，在糖蛋白的合成过程中，其多肽链的合成与糖基化所涉及的反应之间存在调节联系。
