Bafilomycin A1 is a selective inhibitor of vacuolar H+ ATPases (V-ATPases) with I50 values of 4-400 nmol/mg 1.
Bafilomycin A1 was treated to different types of membrane ATPases with the dependent I50 of 400 nmol/mg, 4 nmol/mg and 50 nmol/mg for the vacuolar ATPases of a fungus (N. crassa), a plant (Z. mays), and an animal (bovine abrenal medulla). In addition, the inhibitory effect of bafilomycin A1 on vacuolar ATPases was further determined by testing its influence on H+-pumping activity. H+ translocation was completely inhibited by 10 nM bafilomycin A1 1. Other study has shown that bafilomycin A1 strongly inhibited the pit-forming activity of osteoclasts. The subcellular localization of V-ATPase in osteoclasts was been treated with or without bafilomycin A1 by immunoelectron microscopy. These results suggested that disruption of V-ATPase localization to the ruffled border by bafilomycin A1 resulted in the lack of acidification of the dentine surface 2.
Notes: I50 values is umol of bafilomycin AI per mg of protein giving 50% inhibition of ATPase activity.
References:
1.?Bowman E J, Siebers A, Altendorf K. Bafilomycins: a class of inhibitors of membrane ATPases from microorganisms, animal cells, and plant cells[J]. Proceedings of the National Academy of Sciences, 1988, 85(21): 7972-7976.
2.?Takami M, Suda K, Sahara T, et al. Involvement of vacuolar H+-ATPase in incorporation of risedronate into osteoclasts[J]. Bone, 2003, 32(4): 341-349.
