Markovic O, Stovícková J, Jörnvall H
Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia.
J Protein Chem. 1996 Feb;15(2):127-30. doi: 10.1007/BF01887393.
The role of histidine residues in pectinesterases was evaluated by monitoring the sensitivity to modification with diethyl pyrocarbonate in the tomato and Aspergillus niger enzymes. Different and incomplete losses of enzyme activity were obtained. Inactivation of the enzymes was proportional to the histidine content (two in the tomato T1 form, six in the Aspergillus form), suggesting that accessible histidine residues do not have active-site functions in these pectinesterases, but contribute to the overall structural stability. Lack of His roles in common between the enzyme forms is in agreement with the structures of pectinesterases having no conserved His residues.
通过监测番茄和黑曲霉果胶酯酶对焦碳酸二乙酯修饰的敏感性，评估了组氨酸残基在果胶酯酶中的作用。获得了不同程度且不完全的酶活性丧失。酶的失活与组氨酸含量成正比（番茄T1形式中有两个，黑曲霉形式中有六个），这表明可接近的组氨酸残基在这些果胶酯酶中不具有活性位点功能，但有助于整体结构稳定性。酶形式之间缺乏共同的组氨酸作用，这与果胶酯酶结构中没有保守的组氨酸残基是一致的。
