Open AccessHalobacterial adenosine triphosphatases and the adenosine triphosphatase from Halobacterium saccharovorum
Author(s) -
Kristjansson Hordur,
Sadler Martha H.,
Hochstein Lawrence I.
Publication year - 1986
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1986.tb01856.x
Subject(s) - atpase , hydrolysis , biochemistry , atp hydrolysis , halobacterium , enzyme , chemistry , adenosine triphosphatase , adenosine , protein subunit , nucleotide , adenosine triphosphate , ionic strength , membrane , bacteriorhodopsin , organic chemistry , aqueous solution , gene
Membranes prepared from various members of the genus Halobacterium contained a Triton X‐100 activated adenosine triphosphatase. The enzyme from Halobacterium saccharovorum was unstable in solutions of low ionic strength (< 3 M NaCl) and maximally active in the presence of 3.5 M NaCl. A variety of nucleotide triphosphates was hydrolyzed. MgADP, the product of ATP hydrolysis, was not hydrolyzed and was a competitive inhibitor with respect to MgATP. The enzyme from H. saccharovorum was composed of at least 2 and possibly 4 subunits. The 83‐kDa and 60‐kDa subunits represented about 90% of total protein. The 60‐kDa subunit reacted with dicyclohexylcarbodiimide (DCCD) when inhibition was carried out in an acidic medium. The significance of the two minor components (28 kDa and 12 kDa) is not established. The enzyme from H. saccharovorum , which differs from previously described halobacterial ATPases, possesses properties of an F 1 F 0 as well as an E 1 E 2 ATPase.