期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2003
卷号：100
期号：19
页码：10641-10646
DOI：10.1073/pnas.1934562100
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：An enantio-specific polyphenol oxidase (PPO) was purified {approx}1,700-fold to apparent homogeneity from the creosote bush (Larrea tridentata), and its encoding gene was cloned. The posttranslationally processed PPO ({approx}43 kDa) has a central role in the biosynthesis of the creosote bush 8-8' linked lignans, whose representatives, such as nordihydroguaiaretic acid and its congeners, have potent antiviral, anticancer, and antioxidant properties. The PPO primarily engenders the enantio-specific conversion of (+)-larreatricin into (+)-3'-hydroxylarreatricin, with the regiochemistry of catalysis being unambiguously established by different NMR spectroscopic analyses; the corresponding (-)-enantiomer did not serve as a substrate. This enantio-specificity for a PPO, a representative of a widespread class of enzymes, provides additional insight into their actual physiological roles that hitherto have been difficult to determine.
