title: Trypsin digestion for determining orientation of ATPase in Halobacterium saccharovorum membrane vesicles.
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.
authors.affiliation: NASA, Ames Research Center, Moffett Field, CA 94035, USA.
authors.forename: H
authors.initials: H
authors.lastname: Kristjansson
authors.forename: L I
authors.initials: LI
authors.lastname: Hochstein
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D006217:Halobacterium / Q000201:enzymology* / Q000648:ultrastructure*; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000378:metabolism*; D017830:Octoxynol / Q000737:chemistry; D014357:Trypsin / Q000378:metabolism*
chemical_list: D017830:Octoxynol; D016660:NAD(P)H Dehydrogenase (Quinone); D014357:Trypsin; D000251:Adenosine Triphosphatases