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首页> 外文期刊>Journal of bacteriology >Enzymatic depolymerization of emulsan.
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Enzymatic depolymerization of emulsan.

机译：乳胶的酶解聚。

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Emulsan, the polyanionic emulsifying agent synthesized by Acinetobacter calcoaceticus RAG-1, was depolymerized by an enzyme obtained from a soil bacterium YUV-1. The extracellular emulsan depolymerase was produced when strains RAG-1 and YUV-1 were grown together on agar medium. The enzyme was extracted from the agar and concentrated by ultrafiltration and ammonium sulfate precipitation. The molecular weight of the enzyme was estimated to be 89,000. Emulsan depolymerase activity was due to an eliminase reaction which split glycosidic linkages within the heteropolysaccharide backbone of emulsan to generate reducing groups and alpha, beta-unsaturated uronides with an absorbance maximum of 233 nm. Deesterified emulsan was degraded by emulsan depolymerase at only 27% of the rate of the native polymer. The treatment of emulsan solutions with emulsan depolymerase for brief periods caused a rapid and parallel drop in viscosity and emulsifying activity. More than 75% of the viscosity and emulsifying activity was lost at a time when less than 0.5% of the glycosidic linkages were broken. These data indicate that (i) emulsan depolymerase is an endoglycosidase and (ii) the higher the molecular weight of emulsan, the greater its emulsifying activity. Exhaustive digestion of emulsan with emulsan depolymerase produced oligosaccharides with a number average molecular weight of about 3,000. The fractionation of the digest on Bio-Gel P-6 yielded four broad peaks. The pooled fractions from each of the peaks contained the same relative amounts of reducing sugar and had an absorbance at 233 nm. The molar ratio of esterified sugar to reducing groups was close to 2 in each fraction.
机译：由土壤不动杆菌RAG-1合成的聚阴离子乳化剂Emulsan由土壤细菌YUV-1获得的酶解聚。当菌株RAG-1和YUV-1在琼脂培养基上一起生长时，产生了细胞外Emulsan解聚酶。从琼脂中提取酶，并通过超滤和硫酸铵沉淀进行浓缩。该酶的分子量估计为89,000。 Emulsan解聚酶的活性归因于消除酶的反应，该酶分解了Emulsan杂多糖主链内的糖苷键以生成还原基团和最大吸光度为233 nm的α，β-不饱和铀酰。脱去酯的乳液被乳液解聚酶降解的程度仅为天然聚合物的27％。短期内用乳聚糖解聚酶处理乳溶液会导致粘度和乳化活性迅速平行下降。当少于0.5％的糖苷键断裂时，损失了超过75％的粘度和乳化活性。这些数据表明（i）乳聚糖解聚酶是一种内切糖苷酶，和（ii）乳聚糖的分子量越高，其乳化活性越大。用乳聚糖解聚酶彻底消化乳聚糖产生数均分子量为约3,000的寡糖。在Bio-Gel P-6上的消化物分馏产生了四个宽峰。来自每个峰的合并的级分包含相同的相对量的还原糖，并且在233 nm处具有吸光度。在每个部分中，酯化糖与还原基团的摩尔比接近2。

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