Crotti L B, Terenzi H F, Jorge J A, de Lourdes M, Polizeli M L
Departamento de Biologia, Faculdade de Filosofía, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Brazil.
J Basic Microbiol. 1998;38(3):181-8.
The exo-1 mutant of Neurospora crassa produced and secreted pectolytic activities when incubated in the presence of pectin-containing biological materials. This study shows that polygalacturonase, pectate lyase and pectin lyase activities were induced in media supplemented with galactose or galacturonic acid, indicating that these sugars induced the synthesis of pectinases. Pectinesterase activity was undetectable. Polygalacturonase activity was better induced by galactose than by galacturonic acid. The reverse was true for lyase activities. The inducing effect of galactose and galacturonic acid seemed to be different: (i) a mixture of galactose and galacturonic acid synergistically increased the production of pectic enzymes, as compared to that in the presence of one of these sugars; (ii) the inducing effect of galacturonic acid was partially repressed by glucose; (iii) in contrast, the inducing effect of galactose, rather than repressed, was enhanced by the presence of glucose. Altogether, these data point out to a complex mechanism of regulation of pectolytic enzymes by pectin-containing organic substances.
粗糙脉孢菌的exo - 1突变体在含有果胶的生物材料存在下培养时，会产生并分泌果胶分解活性物质。本研究表明，在添加半乳糖或半乳糖醛酸的培养基中会诱导产生多聚半乳糖醛酸酶、果胶酸裂解酶和果胶裂解酶活性，这表明这些糖类诱导了果胶酶的合成。未检测到果胶酯酶活性。半乳糖比半乳糖醛酸更能有效地诱导多聚半乳糖醛酸酶活性。裂解酶活性的情况则相反。半乳糖和半乳糖醛酸的诱导作用似乎有所不同：(i) 与单独存在其中一种糖类相比，半乳糖和半乳糖醛酸的混合物能协同增加果胶酶的产量；(ii) 葡萄糖会部分抑制半乳糖醛酸的诱导作用；(iii) 相反，葡萄糖的存在会增强而非抑制半乳糖的诱导作用。总之，这些数据表明含果胶的有机物质对果胶分解酶的调节机制很复杂。
