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Characterization and effect of light on the plasma membrane H(+) -ATPase of bean leavesProton excretion from bean (Phaseolus vulgaris L.) leaf cells is increased by bright white light. To test whether this could be due, at least in part, to an increase in plasma membrane (PM) ATPase activity, PM vesicles were isolated from primary leaves by phase partitioning and used to characterize PM ATPase activity and changes in response to light. ATPase activity was characterized as magnesium ion dependent, vanadate sensitive, and slightly stimulated by potassium chloride. The pH optimum was 6.5, the Km was approximately 0.30 millimolar ATP, and the activity was about 60% latent. PM vesicles were prepared from leaves of plants grown for 11 days in dim red light (growing slowly) or grown for 10 days in dim red light and then transferred to bright white-light for 1 day (growing rapidly). For both light treatments, ATPase specific activity was approximately 600 to 700 nanomoles per milligram protein per minute, and the latency, Km, and sensitivity to potassium chloride were also similar. PM vesicles from plants grown in complete darkness, however, exhibited a twofold greater specific activity. We conclude that the promotion of leaf growth and proton excretion by bright white light is not due to an increase in ATPase specific activity. Light does influence ATPase activity, however; both dim red light and bright white light decreased the ATPase specific activity by nearly 50% as compared with dark-grown leaves.
Document ID
20040090439
Document Type
Reprint (Version printed in journal)
Authors
Linnemeyer, P. A. (University of Washington Seattle 98195, United States)
Van Volkenburgh, E.
Cleland, R. E.
Date Acquired
August 21, 2013
Publication Date
January 1, 1990
Publication Information
Publication: Plant physiology
Volume: 94
ISSN: 0032-0889
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: DCB-8517349
Distribution Limits
Public
Copyright
Other
Keywords
NASA Program Space Biology
NASA Discipline Plant Biology
NASA Discipline Number 29-20
Non-NASA Center