Chymostatin (9076-44-2) is a potent, competitive, slow-binding inhibitor of a-, b-, g-, d-chymotrypsin, papain and cathepsins B/G (chymotryptase-like serine proteases)1, Ki=9.36 and 13.1 nM for chymotrypsin and chymase2. Cathepsin G Ki=0.15 mM.3 Consists of a mixture of type A (L-Leu), B (L-Val) and C (L-Ile) forms.1 Decreases plasma and tissue levels of angiotensin II without lowering mean blood pressure in a hypertensive rat model.4 Commonly used in lysis buffers to prevent degradation of proteins. Typical working concentration is 6-60 µg/ml.
1) Umezawa et al. (1970), Chymostatin, a new chymotrypsin inhibitor produced by actinomycetes; J. Antibiot. (Tokyo) 23 425
2) Johnson et al. (1998), Inactivation of chymotrypsin and human skin chymase: kinetics of time-dependent inhibition in the presence of substrate; Biochim. Biophys. Acta 953 269
3) Stein and Strimpler (1987), Slow-binding of chymotrypsin and cathepsin G by the peptide aldehyde chymostatin; Biochemistry 26 2611
4) Roszkowska-Chojecka et al. (2015), Effects of chymostatin, a chymase inhibitor, on blood pressure, plasma and tissue angiotensin II, renal haemodynamics and renal excretion in two models of hypertension in the rat; Exp. Physiol. 100 1093