The F1-ATPase from Streptococcus cremoris: Isolation, purification and partial characterization

Abstract 1. 1. The F 1 -ATPase from the plasma membrane of Streptococcus cremoris HA was released by low ionic shock wash and purified by gel filtration and ion exchange chromatography. 2. 2. The specific activity of the purified F 1 -ATPase was 25.8 μmol P i /mg protein/min. 3. 3. K m for ATP was 0.80 mM, and K i for ADP as a competetive inhibitor 0.40 mM. 4. 4. The purified F 1 -ATPase consisted of five subunits, α, β, γ, δ and ϵ, with molecular masses of 47.0, 45.0, 29.5, 22.0 and 13.0 kDa, respectively. 5. 5. The isoelectric point of the enzyme complex was found to be 4.4.