科研之友
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摘要
Acid phosphatases (EC 3.1.3.2) are enzymes catalyzing the hydrolysis of different orthophosphate esters. They are abundant among both plant and animal tissues. Acid phosphatases can be divided into few groups of enzymes with differential substrate specifity and cellular localization. High substrate specific acid phosphatases are relatively well described and their role in metabolic processes is well known. On the other hand, role of nonspecific acid phosphatases is still not clear. Acid phosphatases can be divided in terms of localization on extracellular (take part in Pi scavenging from soil) and intracellular (play role in Pi mobilization from internal organic phosphorus sources). Nonspecific acid phosphatases take part in plant reaction not only on phosphorus deficiency but also water stress and pathogen defense. Purple acid phosphatases are the largest group of nonspecific phosphatases containing metal ions in their active site. Plant purple acid phosphatases can be distinguished into small (about 35 kDa) and large (about 55 kDa). They play a significant role not only in Pi releasing from unavailable, organic Pi sources but probably also in reactive oxygen species scavenging during senescence or in stressed tissues. However their role in plant metabolism is currently under investigation. In contrast, phytases are highly specific phosphatases which hydrolyze phytic acid (and phytates). These enzymes hydrolyze storage forms of phosphorus in seeds but they can also be secreted into the rhizosphere by microorganisms and some plants. This review summarizes our current knowledge about diverse roles of acid phosphatases, especially their role in plant phosphorus nutrition.
- 出版日期2009
