Trypsin digestion for determining orientation of ATPase in Halobacterium saccharovorum membrane vesicles |
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Authors: | Hordur Kristjansson Lawrence I Hochstein |
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Institution: | NASA, Ames Research Center, Moffett Field, CA 94035, U.S.A. |
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Abstract: | Abstract Membranes prepared by low pressure disruption of cells exhibited no ATPase activity in the absence of Triton X-100, although 43% of the total menadione reductase activity was detected. Trypsin digestion reduced menadione reductase activity by 45% whereas ATPase activity was not affected. Disruption of the membrane fraction at higher pressure solubilized about 45% of the ATPase activity. The soluble activity was still enhanced by Triton X-100, suggesting that the detergent, besides disrupting membrane vesicles, also activated the ATPase. The discrepancy in localization of menadione reductase and ATPase activities raised questions regarding the reliability of using a single marker enzyme as an indicator of vesicle orientation. |
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Keywords: | Vesicle orientation Archaebacteria enzyme markers ATPase Triton X-100 activated menadione reductase |
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