“…zyme and amino acid sequence data all indicate that the plant plasma membrane proton pump belongs to the Ptype class of proton pumps (Schaller and Sussman, 1988b). Other well-characterized members of this group whose genes have been cloned and sequenced include (1) the fungal plasma membrane proton pump (H+-ATPase) (Hager et al, 1986;Serrano, Kielland-Brandt, and Fink, 1986) as well as a putative proton pump in the plasma membrane of the protozoan, Leishmania donovani (Meade et al, 1989); (2) the Na+,K+-ATPase in mammalian plasma membrane (Shull, Schwartz, and Lingrell, 1985;Shull and Lingrel, 1987); (3) the K+-ATPase of bacterial plasma mem? branes (Walderhaug, Litwack, and Epstein, 1989); (4) an FT.rC-ATPase in mammalian stomach (Shull and Lingrel, 1986;Maeda, Ishizaki, and Futai, 1988); (5) the Ca2+-ATPase of mammalian plasma membrane (Shull and Greeb, 1988;Verma et al, 1988); and (6) the Ca2+-ATPase of mammalian sarcoplasmic and endoplasmic reticulum (MacLennan et al, 1985;Brandl et al, 1986;Lytton and MacLennan, 1988;Lytton et al, 1989).…”