Greiner R, Alminger M L, Carlsson N G
Centre for Molecular Biology, Federal Research Centre for Nutrition, Haid-und-Neu-Strasse 9, D-76131 Karlsruhe, Germany, and Department of Food Science, Chalmers University of Technology, c/o SIK, Box 5401, SE-402 29 Göteborg, Sweden.
J Agric Food Chem. 2001 May;49(5):2228-33. doi: 10.1021/jf0100090.
During food processing such as baking, phytate is dephosphorylated to produce degradation products, such as myo-inositol pentakis-, tetrakis-, tris-, bis-, and monophosphates. Certain myo-inositol phosphates have been proposed to have positive effects on human health. The position of the phosphate groups on the myo-inositol ring is thereby of great significance for their physiological functions. Using a combination of high-performance ion chromatography analysis and kinetic studies the stereospecificity of myo-inositol hexakisphosphate dephosphorylation by a phytate-degrading enzyme from baker's yeast (Saccharomyces cerevisiae) was established. The data demonstrate that the phytate-degrading enzyme from baker's yeast dephosphorylates myo-inositol hexakisphosphate in a stereospecific way by sequential removal of phosphate groups via D-Ins(1,2,4,5,6)P(5), D-Ins(1,2,5,6)P(4), D-Ins(1,2,6)P(3), D-Ins(1,2)P(2), to finally Ins(2)P (notation 3/4/5/6/1). Knowledge of the absolute stereochemical specificity of the baker's yeast phytase allows use of the enzyme to produce defined myo-inositol phosphates for kinetic and physiological studies.
在烘焙等食品加工过程中，植酸会发生去磷酸化反应，生成降解产物，如肌醇五磷酸、四磷酸、三磷酸、二磷酸和单磷酸。某些肌醇磷酸已被认为对人体健康有积极作用。因此，磷酸基团在肌醇环上的位置对其生理功能具有重要意义。通过结合高效离子色谱分析和动力学研究，确定了面包酵母（酿酒酵母）中一种植酸降解酶对肌醇六磷酸去磷酸化的立体特异性。数据表明，面包酵母中的植酸降解酶通过依次去除磷酸基团，以立体特异性方式使肌醇六磷酸去磷酸化，依次生成D-Ins(1,2,4,5,6)P(5)、D-Ins(1,2,5,6)P(4)、D-Ins(1,2,6)P(3)、D-Ins(1,2)P(2)，最终生成Ins(2)P（标记为3/4/5/6/1）。了解面包酵母植酸酶的绝对立体化学特异性，有助于利用该酶生产特定的肌醇磷酸，用于动力学和生理学研究。
