Gottschalk T E, Nielsen J E, Rasmussen P
Danisco Biotechnology, Copenhagen K, Denmark.
Appl Microbiol Biotechnol. 1996 Mar;45(1-2):240-4. doi: 10.1007/s002530050677.
An endogenous beta-glucuronidase that hydrolyses the chromogenic substrate 5-bromo-4-chloro-3-indolyl-beta-D-glucuronide (X-gluc) in Aspergillus niger is reported. The activity was induced when the fungus was grown in media containing xylan, but was either very low, or absent, when grown on glucose. Endogenous beta-glucuronidase was primarily located in newly formed hyphae, and was apparent at pH values between 3 and 6. Hydrolysis of X-gluc was sensitive to the inhibitor D-saccharic acid 1,4-lactone and was irreversibly inactivated by heating. The bacterial uid A beta-glucuronidase reporter gene was strongly expressed in the hyphae of transformed A. niger but, in contrast to the endogenous activity, the enzyme was also active at pH 7-8.5. Histochemical localization of uidA expression in A. niger, without interference from the endogenous beta-glucuronidase activity, was achieved by staining at this pH.
据报道，黑曲霉中存在一种内源性β-葡萄糖醛酸酶，它能水解生色底物5-溴-4-氯-3-吲哚基-β-D-葡萄糖醛酸苷（X-葡糖）。当真菌在含有木聚糖的培养基中生长时，该酶的活性被诱导，但在以葡萄糖为培养基生长时，活性很低或没有活性。内源性β-葡萄糖醛酸酶主要位于新形成的菌丝中，在pH值为3至6时活性明显。X-葡糖的水解对抑制剂D-糖二酸1,4-内酯敏感，加热会使其不可逆地失活。细菌uid Aβ-葡萄糖醛酸酶报告基因在转化后的黑曲霉菌丝中强烈表达，但与内源性活性不同的是，该酶在pH值为7 - 8.5时也有活性。通过在此pH值下染色，实现了黑曲霉中uidA表达的组织化学定位，且不受内源性β-葡萄糖醛酸酶活性的干扰。
