Bafilomycin D is a potent inhibitor of vacuolar H+ ATPases (V-ATPases) with IC50 value of approximately 2 nM for the V-ATPase from the fungus N. crassa [1].
Ion pumps use the energy provided by the hydrolysis of ATP to energize ion-transport processes across cell membranes. ATPases can be distinguished to P-type, F-type and V-type ATPases. P-type ATPases have a phosphorylated transitional stage, F-type ATPases are primarily used in ATP synthesis, and V-type ATPases are genetically and functionally related to F-ATPases but function only in ATP breakdown [1].
The bafilomycins are fungal plecomacrolide class macrolide antibiotics isolated from the culture medium of Streptomyces sp. and are also high-affinity inhibitors of V-ATPases and can be used to study specifically the function of this type of ATPase. They inhibited the growth of Gram-positive bacteria and fungi. Bafilomycin C1 inhibited the enzymatic activity of the Na+, K+-ATPase with Ki value of 11 μmol/l and showed anthelmintic activity against Caenorhabditis elegans [1][2].
References:
[1]. Drse S, Altendorf K. Bafilomycins and concanamycins as inhibitors of V-ATPases and P-ATPases. J Exp Biol. 1997 Jan;200(Pt 1):1-8.
[2]. Bowman EJ, Siebers A, Altendorf K. Bafilomycins: a class of inhibitors of membrane ATPases from microorganisms, animal cells, and plant cells. Proc Natl Acad Sci U S A. 1988 Nov;85(21):7972-6.