Complexation, stabilization, and UV photolysis of extracellular and surface-bound glucosidase and alkaline phosphatase: Implications for biofilm microbiota
Complexation, stabilization, and UV photolysis of extracellular and surface-bound glucosidase and alkaline phosphatase: Implications for biofilm microbiota
复制标题
DOI：
10.1007/s00248-001-1023-7
复制
发表时间：
2001-11-01
影响因子：
3.6
通讯作者：
Wetzel, RG
中科院分区：
文献类型：
--
作者：
Espeland, EM;Wetzel, RG
生物膜生产和商业纯化的α-和β-葡萄糖苷酶和碱性磷酸酶进行不同的光谱部分的自然和人工光，并暴露于各种腐殖物质，以阐明其对酶活性的影响。所有酶的光化学降解发生在光谱的不同部分。UVB辐照产生的酶的最大的整体光化学降解，与UVA和PAR辐照发生显着的速率。酶与腐殖物质的络合导致酶的抑制、稳定和光化学保护。酶活性的抑制发生在腐殖物质的存在下，通过整体酶活性的减少。然而，腐殖酸-酶复合也通过限制酶降解而导致稳定，同时保持高活性。暴露于自然和人工光源的酶有显着降低酶活性的腐殖物质的存在下，这表明，腐殖酸酶复合物可以保护光诱导的光化学降解的酶。细菌表面结合的α-和β-葡萄糖苷酶的活动显着降低腐殖物质的存在下。生物膜群落内光合作用诱导的pH变化可导致α-和β-葡糖苷酶活性的大幅降低，同时增强碱性磷酸酶的水解活性。
Biofilm-produced and commercially-purified alpha- and beta -glucosidase and alkaline phosphatase were subjected to different spectral portions of natural and artificial light and exposed to various humic substances to elucidate their impact on enzyme activities. Photochemical degradation of all enzymes occurred under different portions of the light spectrum. UVB irradiance produced the greatest overall photochemical degradation of enzymes, with significant rates occurring with UVA and PAR irradiance. The complexation of enzymes with humic substances resulted in inhibition, stabilization, and photochemical protection of the enzyme. Inhibition of enzyme activity occurred via reductions in overall enzyme activity in the presence of humic substances. However, humic-enzyme complexation also resulted in stabilization by restricting enzyme degradation while retaining high activities. Enzymes exposed to natural and artificial light sources had significantly lower reductions in enzyme activities in the presence of humic substances, which indicates that humic-enzyme complexes may protect enzymes from light-induced photochemical degradation. Bacterial surface-bound alpha- and beta -glucosidase activities were significantly reduced in the presence of humic substances. Photosynthetically induced pH changes within biofilm communities can cause large reductions in alpha- and beta -glucosidase activities while enhancing the hydrolytic activity of alkaline phosphatase.