Inhibition of Membrane-Bound Adenosine Triphosphatase Activity fromNicotiana tabacumL. Leaves with Alkyltrimethylammonium Bromide

摘要

Cetyltrimethylammonium bromide (CTAB), a cationic detergent, more effectively inhibited the activity of membrane-bound epidermal adenosine triphosphatase (ATPase) of tobacco (Nicotiana tabacumL. cv. Samsun) leaves than anionic or non-ionic detergents. The inhibition of ATPase activity was highly dependent on the length of the alkyl chain of alkyltrimethylammonium: CTAB>dodecyltrimethylammonium bromide>n-octyltrimethylammonium bromide≒trimethylammonium chloride≒cetyl bromide, compared at 10−4M. The last three derivatives hardly inhibited the activity. CTAB inhibition was equivalent to that due to other cationic detergents, cetylpyridinium bromide and cetyl amine, but less than that by gramicidin S and tyrocidine and stronger than that byN,N'-dicyclohexylcarbodiimide and vanadate.These results show that a certain length of the alkyl chain (Cn>12) and the combination of both hydrophobic and charged groups of a detergent moiety are indispensable for inhibiting the membrane-bound epidermal ATPase act