This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Yoshida, S. Articles by Niki, T. Search for Related Content PubMed PubMed Citation Articles by Yoshida, S. Articles by Niki, T. Agricola Articles by Yoshida, S. Articles by Niki, T.

Articles

Properties of Plasma Membrane Isolated from Chilling-Sensitive Etiolated Seedlings of Vigna radiata L. ^1,2

The Institute of Low Temperature Science, Hokkaido University, Sapporo 060, Japan

Plasma membrane was isolated in a uniform population and with a high purity from chilling-sensitive etiolated young seedlings of Vigna radiata (mung bean) utilizing an aqueous two polymer phase separation system and subsequent sucrose density gradient. The isolated plasma membrane was associated with vanadate-sensitive and KNO₃-insensitive ATPase. The ATPase has high specificities both for substrate and Mg²⁺ ion with optimum pH at 6.5. It was slightly stimulated by monovalent anions, especially Cl^–. Proton ionophores such as gramicidin D and carbonyl cyanide p-trifluoromethoxyphenylhydrazone did not stimulate the enzyme activity. The ATPase is apparently latent and highly stimulated by the addition of detergents such as Triton X-100. A maximum stimulation was achieved by the addition of 0.02% Triton X-100. After treatment with proteinase K in an isotonic buffer solution, the enzyme activity was less affected, whereas the peptides were specifically digested. Based on these facts, the isolated plasma membrane vesicles appear to be tightly sealed and in a right-side-out orientation. The plasma membrane ATPase had two inflection points at higher (18.9°C) and lower (6.7°C) temperatures on the Arrhenius plots of the activity. The lower inflection temperature apparently coincided with that of the anisotropy parameter of embedded 1,6-diphenyl-1,3,5-hexatriene, indicating that the membrane bound ATPase activity was affected by a phase transition of membrane lipids and/or temperature-dependent conformational changes in the enzyme molecules per se. Considering the fact that the plant material used here is highly sensitive to chilling temperatures and injured severely by exposure to temperatures below 5°C for a relatively short period, the thermotropic properties of membrane molecules are considered to be involved in the mechanism of chilling injury.

² Contribution No. 2763 from the Institute of Low Temperature Science.

This article has been cited by other articles:

				Y. Takeda and K. Kasamo In Vitro Fusion of Plant Golgi Membranes Can Be Influenced by Divalent Cations J. Biol. Chem., November 27, 2002; 277(49): 47756 - 47764. [Abstract] [Full Text] [PDF]

				M. Sacande, E. A. Golovina, A. C. van Aelst, and F. A. Hoekstra Viability loss of neem (Azadirachta indica) seeds associated with membrane phase behaviour J. Exp. Bot., May 1, 2001; 52(358): 919 - 931. [Abstract] [Full Text] [PDF]

				T. Hamada, H. Kodama, K. Takeshita, H. Utsumi, and K. Iba Characterization of Transgenic Tobacco with an Increased alpha -Linolenic Acid Level Plant Physiology, October 1, 1998; 118(2): 591 - 598. [Abstract] [Full Text]