Food Engineering and Technology Department, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga, Mumbai 400 019, India.
Carbohydr Polym. 2012 Nov 6;90(4):1811-7. doi: 10.1016/j.carbpol.2012.07.078. Epub 2012 Aug 4.
The influence of enzyme polysaccharide interaction on enzyme stability and activity was elucidated by covalently binding dextran to a model enzyme, α-amylase. The conjugation process was optimized with respect to concentration of oxidizing agent, pH of enzyme solution, ratio of dextran to enzyme concentration, temperature and time of conjugate formation, and was found to affect the stability of α-amylase. α-Amylase conjugated under optimized conditions showed 5% loss of activity but with enhanced thermal and pH stability. Lower inactivation rate constant of conjugated α-amylase within the temperature range of 60-80 °C implied its better stability. Activation energy for denaturation of α-amylase increased by 8.81 kJ/mol on conjugation with dextran. Analysis of secondary structure of α-amylase after covalent binding with dextran showed helix to turn conversion without loss of functional properties of α-amylase. Covalent bonding was found to be mandatory for the formation of conjugate.
通过将葡聚糖共价结合到模型酶α-淀粉酶上，阐明了酶-多糖相互作用对酶稳定性和活性的影响。用不同浓度的氧化剂、酶溶液的 pH 值、葡聚糖与酶浓度的比例、形成共轭物的温度和时间对共轭过程进行了优化，发现这会影响α-淀粉酶的稳定性。在优化条件下进行共轭的α-淀粉酶的活性损失了 5%，但热稳定性和 pH 稳定性得到了增强。在 60-80°C 的温度范围内，共轭α-淀粉酶的失活速率常数较低，这意味着其稳定性更好。α-淀粉酶的变性活化能在与葡聚糖共价结合后增加了 8.81 kJ/mol。对与葡聚糖共价结合后的α-淀粉酶的二级结构分析表明，螺旋向转折转化，而α-淀粉酶的功能特性并未丧失。发现共价键合对于形成共轭物是必需的。
