Biomaterial Database

Evidence for the interaction of valine-10 in cystatin C with the S2 subsite of cathepsin B. 1994

P Lindahl, and D Ripoll, and M Abrahamson, and J S Mort, and A C Storer

Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec.

The interactions between wild-type or mutant recombinant forms of human cystatin C and rat cathepsin B were characterized by measuring progress curves for substrate hydrolysis in the presence of inhibitor. The investigation was guided by the use of computer modeling and explores the possibility that amino acid residues in the N-terminal region of cystatin C interact with substrate-binding regions in the target enzyme. With cystatin C that has Val-10 replaced by an Arg residue (Val10Arg cystatin C), the inhibition constant, K(i), increased 31-fold if the isosteric substitution Glu-245 to Gln was made in cathepsin B. When the wild-type form of the inhibitor was used, the corresponding effect on K(i) was less than 2-fold. In a similar study, using cathepsin B in which the substitution to Gln is instead at Glu-171, no such difference in how K(i) is affected was observed. Both Glu-245 and Glu-171 are located in the S2 subsite of cathepsin B. The observed effects on K(i) indicate that the additional positive charge introduced in Val10Arg cystatin C is interacting with the negative charge on Glu-245 in cathepsin B when these two proteins form a complex; the cystatin variant is thus binding in a substratelike manner with this region of the enzyme. Indirectly, these results suggest that when native cystatin C and cathepsin B form a complex, Val-10 in the inhibitor interacts with the S2 subsite of the enzyme. A K(i) value of 0.13 nM was obtained for the interaction of Val10Arg cystatin C with papain.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009838	Oligodeoxyribonucleotides	A group of deoxyribonucleotides (up to 12) in which the phosphate residues of each deoxyribonucleotide act as bridges in forming diester linkages between the deoxyribose moieties.	Oligodeoxynucleotide,Oligodeoxyribonucleotide,Oligodeoxynucleotides
D010206	Papain	A proteolytic enzyme obtained from Carica papaya. It is also the name used for a purified mixture of papain and CHYMOPAPAIN that is used as a topical enzymatic debriding agent. EC 3.4.22.2.	Tromasin
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D002401	Cathepsin B	A lysosomal cysteine proteinase with a specificity similar to that of PAPAIN. The enzyme is present in a variety of tissues and is important in many physiological and pathological processes. In pathology, cathepsin B has been found to be involved in DEMYELINATION; EMPHYSEMA; RHEUMATOID ARTHRITIS, and NEOPLASM INVASIVENESS.	Cathepsin B-Like Proteinase,Cathepsin B1,Cathepsin B Like Proteinase,Proteinase, Cathepsin B-Like
D003198	Computer Simulation	Computer-based representation of physical systems and phenomena such as chemical processes.	Computational Modeling,Computational Modelling,Computer Models,In silico Modeling,In silico Models,In silico Simulation,Models, Computer,Computerized Models,Computer Model,Computer Simulations,Computerized Model,In silico Model,Model, Computer,Model, Computerized,Model, In silico,Modeling, Computational,Modeling, In silico,Modelling, Computational,Simulation, Computer,Simulation, In silico,Simulations, Computer
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein