1992 Fiscal Year Final Research Report Summary

Functions and behavior of a new type of ATPase(phosphatase) in halophytes

Research Project

Project/Area Number	03660087
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	応用生物化学・栄養化学
Research Institution	Kinki University
Principal Investigator	HIRAYAMA Osamu Kinki University, Food Nutrition, Professor, 農学部, 教授 (80032580)
Project Period (FY)	1991 – 1992
Keywords	halophyte / ATPase / phosphatase / membrane-bound enzyme / salt-resistant enzyme
Research Abstract	A new type of ATPase or phosphatase was found in a halophyte, Solsola komaroli. It occurred in two forms of plasma membrane-bound and free, their activity ratio being 4/96. Both forms of the enzyme hydrolyzed phosphate ester of substrates in the following order ; p-nitrophenylphosphate > pyrophosphate > ADP * ATP > AMP. The activities of both enzymes were stimulated by mono- and di-valent cations, and they were strongly inhibited by molybdate and vanadate. From these properties, this enzyme should be accepted as a new type of acid phosphatase. Both forms of the enzyme were resistant to salinity, particularly the membrane-bound form was stimulated by high concentrations of salt. The present enzyme was also found in non-halophytes, soybean and cucumber, and it was distributed at an increasing concentration with an increase in salt tolerance of plants.