Morosoli R
Biochim Biophys Acta. 1985 Dec 18;826(4):202-7. doi: 10.1016/0167-4781(85)90007-7.
In the yeast Cryptococcus albidus, the utilization of xylan as compared to xylose requires at least an inducible endoxylanase enzyme, secreted in the culture medium. The endoxylanase induction was monitored by immunoprecipitation of in vivo and in vitro synthesized products. The mature endoxylanase is a highly glycosylated enzyme with an apparent molecular weight of 48 000. Upon chemical deglycosylation with trifluoromethanesulfonic acid, the molecular weight was reduced to 40 000. Addition of tunicamycin to the culture medium resulted in the synthesis of a modified polypeptide having a molecular weight of 40 000. Poly(A)-containing RNA isolated from the yeast was translated in the rabbit reticulocyte protein-synthesizing system. The appearance of a translatable xylanase mRNA was observed in xylan-grown cells but not in xylose-grown cells. The polypeptide identified as xylanase had a molecular weight of 44 000. This suggests that the xylanase is synthesized as a precursor, containing a peptide signal sequence of 35 residues.
在酵母浅白隐球酵母中，与木糖相比，木聚糖的利用至少需要一种可诱导的内切木聚糖酶，该酶分泌于培养基中。通过对体内和体外合成产物进行免疫沉淀来监测内切木聚糖酶的诱导情况。成熟的内切木聚糖酶是一种高度糖基化的酶，表观分子量为48000。用三氟甲磺酸进行化学去糖基化后，分子量降至40000。向培养基中添加衣霉素导致合成了一种分子量为40000的修饰多肽。从酵母中分离出的含聚腺苷酸的RNA在兔网织红细胞蛋白质合成系统中进行翻译。在以木聚糖生长的细胞中观察到了可翻译的木聚糖酶mRNA的出现，而在以木糖生长的细胞中未观察到。鉴定为木聚糖酶的多肽分子量为44000。这表明木聚糖酶是以前体形式合成的，含有一个35个残基的肽信号序列。
