Ceramide

A4532 Calcineurin Autoinhibitory Peptide

Protein Ser/Thr Phosphatases

Selective inhibitor of Ca²⁺-calmodulin-dependent protein phosphatase (calcineurin) (IC₅₀ ~ 10 mM). Does not inhibit PP1, PP2A or CaM kinase II (IC₅₀ > 100 mM).

A4533 Calyculin A

Protein Ser/Thr Phosphatases

Potent and selective cell-permeable inhibitor of protein phosphatase 1 (IC₅₀ = 0.3 - 0.7 nM) and protein phosphatase 2A (IC₅₀ = 0.5 - 1 nM). Displays > 10,000,000-fold selectivity over PP2B and PP2C.

A4535 DL-AP3

Protein Ser/Thr Phosphatases

Competitive group I metabotropic glutamate receptor antagonist and inhibitor of phosphoserine phosphatase.

A4536 Fostriecin sodium salt

Protein Ser/Thr Phosphatases

Originally identified as an antitumor antibiotic from Streptomyces pulveraceous. Displays potent inhibition of protein phosphatase types 2A (PP2A) and 4 (PP4) with IC₅₀ values of 1.5 nM and 3 nM respectively. Also exhibits weaker inhibition of topoisomerase II (IC₅₀ = 40 μM) and protein phosphatase type 1 (PP1) (IC₅₀ = 131 μM) with no apparent inhibition of protein phosphatase type 2B (PP2B). Active in vivo.

A4537 Fumonisin B1

Protein Ser/Thr Phosphatases

Mycotoxin produced by Fusarium moniliforme. Potently inhibits sphingosine N-acyltransferase (ceramide synthase), causing an accumulation of sphingoid bases (IC₅₀ ~ 75 nM). Also inhibits protein phosphatases; IC₅₀ values are 80, 300, 400, 500 and 3000 μM for PP5, PP2Cα, PP2A, PP1γ2 and PP2B respectively.