Table 1.

Dephosphorylation of the phosphorylated enzymes

Enzyme	Dephosphorylation, %	Dephosphorylation, % + ouabain
HK	36  ± 2	34  ± 4
HN13	34  ± 1	29  ± 4
HN34	55  ± 4*	47  ± 3
HN56	31  ± 5	29  ± 2
HN34/56	102  ± 4*	28  ± 4†

Sf9 membranes (5 μg) of cells infected with viruses expressing H⁺,K⁺-ATPase (HK) or the chimeras were preincubated at 21°C with 0.2 mM EDTA/1.2 mM MgCl₂/50 mM Tris-acetic acid, pH 6.0, with or without 1 mM ouabain. After 10 s of phosphorylation at 21°C with 0.1 μM [γ-³²P]ATP, the enzymes were dephosphorylated in 50 mM Tris-acetic acid, pH 6.0/100 μM ATP, with or without 1 mM ouabain. The phosphorylation level was determined and corrected for that of the mock. Dephosphorylation is expressed as the percentage decrease of the phosphorylation level in 3 s. The data presented are the mean values ± SE of three samples. 

^*Comparison of the dephosphorylation levels of the chimeras and the wild-type enzyme without ouabain (P < 0.05). 

^† Comparison of the dephosphorylation levels with and without ouabain (P < 0.05).