CHYMOSTATIN (C15-1292-152)

General description

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.

Application

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

Biochem/physiol Actions

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.

Quality

Performance tested.

Formula variant

C₃₁H₄₁N₇O₆

Preparation Note

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.

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.

Other Notes

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