Inactivation of cysteine proteases by (acyloxy)methyl ketones using S'-P' interactions

Biochemistry. 2000 May 30;39(21):6498-502. doi: 10.1021/bi0002378.

Abstract

We have synthesized (acyloxy)methyl ketone inactivators of papain, cathepsin B, and interleukin-1beta conversion enzyme (ICE) that interact with both the S and S' subsites. The value of k(inact)/K(i) for these inactivators is strongly dependent on the leaving group. For example, Z-Phe-Gly-CH(2)-X is a poor inactivator of papain when X is OCOCH(3) (k(inact)/K(i) = 2.5 M(-)(1) s(-)(1)) but becomes a potent inactivator when X is OCO-L-Leu-Z (k(inact)/K(i) = 11 000 M(-)(1) s(-)(1)). Since these leaving groups have similar chemical reactivities, the difference in potency must be attributed to interactions with the S' sites. The potency of the leaving group correlates with the P' specificity of papain. Similar results are also observed for the inactivation of cathepsin B by these compounds. A series of inactivators with the general structure Fmoc-L-Asp-CH(2)-X were designed to inactivate ICE. No inhibition was observed when X was OCOCH(3). In contrast, ICE is inactivated when X is OCO-D-Pro-Z (k(inact)/K(i) = 131 M(-)(1) s(-)(1)). These results demonstrate that S'-P' interactions can be utilized to increase the efficacy and selectivity of (acyloxy)methyl ketone inactivators.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Caspase 1 / metabolism
  • Cathepsin B / metabolism
  • Cattle
  • Cysteine Endopeptidases / chemistry
  • Cysteine Endopeptidases / metabolism*
  • Cysteine Proteinase Inhibitors / chemical synthesis
  • Cysteine Proteinase Inhibitors / chemistry
  • Cysteine Proteinase Inhibitors / pharmacology*
  • Drug Design
  • Ketones / chemical synthesis
  • Ketones / chemistry
  • Ketones / pharmacology*
  • Kinetics
  • Papain / metabolism
  • Structure-Activity Relationship

Substances

  • Cysteine Proteinase Inhibitors
  • Ketones
  • Cysteine Endopeptidases
  • Cathepsin B
  • Papain
  • Caspase 1