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：1989
卷号：86
期号：15
页码：5830-5833
DOI：10.1073/pnas.86.15.5830
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Three classes of mutants of Arabidopsis thaliana (L.) Heynhold with alterations in starch metabolism were found to have higher levels of leaf amylase activity than the wild type when grown in a 12-hr photoperiod. This effect was dependent upon the developmental stage of the plants and was largely suppressed during growth in continuous light. The various amylolytic activities in crude extracts were separated by electrophoresis in nondenaturing polyacrylamide gels and visualized by activity staining. The increased amylase activity in the mutants was due to an up to 40-fold increase in the activity of an extrachloroplast {beta}-amylase (EC 3.2.1.2 ). These observations indicate the existence of a regulatory mechanism that controls the amount of {beta}-amylase activity in response to fluctuations in photosynthetic carbohydrate metabolism. It is paradoxical that {beta}-amylase appears to be a highly regulated enzyme, but as yet no physiologically relevant function can be assigned to this enzyme due to the absence of starch in the cytoplasmic compartment of leaf cells.
关键词：phosphoglucomutase ; ADPglucose pyrophosphorylase ; photosynthesis ; photosynthetic CO2 fixation
