Exploration of the primary specificity site of cathepsin B

Journal Article · Fri Apr 15 04:00:00 EST 1983 · Arch. Biochem. Biophys.; (United States)

DOI:https://doi.org/10.1016/0003-9861(83)90540-4· OSTI ID:5013844

Shaw, E; Wikstrom, P; Ruscica, J

Peptidyl diazomethyl ketones inactivate cathepsin B apparently by alkylation of the active center thiol following complex formation as in the case of benzyloxycarbonyl (Cbz)-Phe-AlaCHN/sub 2/. The phenylalanine contributes considerably to binding in the secondary specificity site. In order to define the topography of the active center region comprising the primary specificity site of beef spleen cathepsin B, a series of peptidyl diazomethyl ketones having the general structure Cbz-Phe-X-CHN/sub 2/ has now been synthesized. The amino acid, X, has been varied in size to include rather large side chains which might reveal available binding potential or limitations. Some of the reagents, in fact, were not inhibitory even at 10/sup -4/ M. Others, however, that did measurably inactivate cathepsin B provided a range of reactivities that extended over 5 orders of magnitude and correlated with affinity in the reversible phase of inactivation. Some large side chains, for example that of tryptophan, were very poorly tolerated in this region of the active center, whereas others, such as O-benzyl threonine, provided remarkably active inhibitors. A topographical rationalization of the results is offered.

• Research Organization: Brookhaven National Lab., Upton, NY
• OSTI ID: 5013844
• Journal Information: Arch. Biochem. Biophys.; (United States), Journal Name: Arch. Biochem. Biophys.; (United States) Vol. 222:2; ISSN ABBIA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ALKYLATION
AMINO ACIDS
BIOCHEMISTRY
CARBOXYLIC ACIDS
CATHEPSIN
CHEMICAL REACTIONS
CHEMISTRY
ENZYME ACTIVITY
ENZYMES
HYDROLASES
INACTIVATION
KETONES
MOLECULAR STRUCTURE
ORGANIC ACIDS
ORGANIC COMPOUNDS
PEPTIDE HYDROLASES
SH-PROTEINASES