Palmostatin B

A cell-permeable, beta-lactone acyl protein thioesterase 1 (APT1) inhibitor (IC₅₀ = 0.67 µM, in an enzymatic assay) that is shown to specifically block Ras depalmitoylation, without affecting Ras acylation, in MDCK cells, both in vitro and in vivo. It induces a marked redistribution of NRas to endomembranes (1 µM) without notable cytotoxicity, and is shown to elicit a loss of the precise steady-state localization of palmitoylated Ras proteins in the same cell line. At 50 µM, this inhibitor displays a partial phenotypic reversion in oncogenic HRasG12V-transformed fibroblasts. Furthermore, it demonstrates selectivity for APT1 over phospholipase A1, A2, Cβ and D. It′s inhibitory effect is demonstrated to be consistent with that of APT1 downregulation by siRNA.

Primary Target
APT1

Packaged under inert gas

A 50 mM (2 mg/106.23 µL) sterile-filtered solution of APT1 Inhibitor, palmostatin B (Cat. No. 178501). in DMSO.

Following initial thaw, aliquot and freeze (-20°C). Aliquots are stable for up to 3 months at -20°C.

Dekker, F. and Hedberg, C. 2011. Bioorg. Med. Chem. Lett.19, 1376.

Dekker, F., et al. 2010. Nat. Chem. Biol.6, 449.

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Toxicity: Standard Handling (A)