Inactivation of Calpain I and Calpain II by Specificity-Oriented Tripeptidyl Chloromethyl Ketones

• Published in: Journal of biochemistry (Tokyo) Vol. 99; no. 1; pp. 173 - 179
• Main Authors: SASAKI, Takashi, KIKUCHI, Takanobu, FUKUI, Ichiro, MURACHI, Takashi
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.01.1986
• Subjects: Alkylation; Amino Acid Chloromethyl Ketones - chemical synthesis; Amino Acid Chloromethyl Ketones - pharmacology; Analytical, structural and metabolic biochemistry; Biological and medical sciences; calpain; Calpain - antagonists & inhibitors; Caseins - pharmacology; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; Hydrolases; Kinetics; Oxidation-Reduction; Structure-Activity Relationship; Tosylphenylalanyl Chloromethyl Ketone - pharmacology; tripeptidyl chloromethyl ketones; Vertebrata; Molecular form; Mammalia; Synthetic product; Enzyme inhibitor; Calpain; Artiodactyla; Kinetic parameter; Ungulata; Pig
• ISSN: 0021-924X; 1756-2651
• DOI: 10.1093/oxfordjournals.jbchem.a135457

Three new tripeptidyl chioromethyl ketones, Leu-Leu-XCH2Cl, with X representing Phe, Tyr, or Lys, were synthesized and their potencies to inactivate calpains I and II were compared. They were designed to fulfil the specificity requirement of calpains established recently. When compared in terms of the dose for 50% inactivation, Leu-Leu-PheCH2Cl was the strongest inactivator, being 500–600 times more effective than tosyl-PheCH2Cl and 5–14 times more than N-[N-(L-3-trans-carboxyoxiran-2-carbonyl)-L-leucyl]agmatine (E-64). The potency toward calpain, either I or II, decreased in the order Phe > Tyr > Lys derivatives > E-64, whereas that toward papain was E-64 > Lys > Phe > Tyr derivatives. From the determined kinetic parameters, the Phe derivative was 18.3 and 16.6 times more effective than E-64 on calpains I and II, respectively. Likewise, the rate of the alkylation reaction by these chloromethyl ketones with calpain I was 2–4 times greater than that with calpain II. Leu-Leu-PheCH2Cl and its N-dansylated product should be useful for highly selective affinity labeling of calpains I and II.