Chymostatin

Chymostatin is a mixture of three components, A, B, and C. The component A being N-[((S)-1-carboxy-2-phenylethyl)-carbamoyl]-α-[2-iminohexahydro-4(S)-pyrimidyl]-L-glycyl-L-leucyl-phenylalaninal. The other two components B and C differ in that the L-leucyl residue is substituted by L-valine and L-isoleucine, respectively.

Chymostatin is a specific inhibitor of α-, β-, γ-, and δ-chymotrypsin.

Chymostatin is a strong inhibitor of many proteases, including chymotrypsin, papain, chymotrypsin-like serine proteinases, chymases, and lysosomal cysteine proteinases such as cathepsins A,B,C, B, H, and L. It weakly inhibits human leucocyte elastase. It is effective at a final concentration of 100 to 200 μg/ml (10 to 100 μM). Chymostatin is often included in protease inhibitor cocktails used with plant extracts.

Working concentration: 6 to 60 μg/ml (10 to 100 μM)
1 U chymotrypsin is inhibited to 49% of the original activity by 1.8 μg of chymostatin.
Thin-layer chromatography: butanol/methanol/H₂O = 4 / 1 / 2
Working solution: Soluble in glacial acetic acid or DMSO to 20 mg/ml. Sparingly soluble in water, methanol, or ethanol. Insoluble in ethyl acetate, petroleum and ethyl ethers, hexane, or chloroform (CHCl₃).
It is recommended to dissolve the inhibitor in 1% acetic acid in higher concentration and to adjust the concentration wanted with phosphate buffer, 0.05 M, pH 7.0, which is common for chymotrypsin assay.
CAUTION: DMSO (Dimethyl sulfoxide) will permeate the skin, carrying solubilized protease inhibitors. Always wear appropriate protection for eyes, skin, etc.
Storage conditions (working solution): -15 to -25 °C
Dilute solutions should be stored frozen in aliquots at -15 to -25 °C and are stable for approximately one month. Avoid repeated freezing. Growth of microorganisms should be avoided as proteases from microbial origin may hydrolyze the peptides.

C₃₁H₄₁N₇O₆

Solubility testing in glacial acetic acid at 10 mg/ml yields a clear solution, which is usually colorless, but can be yellow in appearance. It is reportedly also soluble in DMSO; only slightly soluble in water and short-chain alcohols; insoluble in ethyl acetate, butyl acetate, ether, hexane, and petroleum ether. Stock solutions (10 mM) can be prepared in DMSO and are stable for months at -20 °C. Stock solutions can also be made in 0.1 M HCl. Dilute solutions (10-100 μM) are only stable for several hours, due to oxidation of the terminal aldehyde.

Performance tested.

For life science research only. Not for use in diagnostic procedures.