A group of lysosomal proteinases or endopeptidases found in aqueous extracts of a variety of animal tissues. They function optimally within an acidic pH range. The cathepsins occur as a variety of enzyme subtypes including SERINE PROTEASES; ASPARTIC PROTEINASES; and CYSTEINE PROTEASES.
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.
An aspartic endopeptidase that is similar in structure to CATHEPSIN D. It is found primarily in the cells of the immune system where it may play a role in processing of CELL SURFACE ANTIGENS.
A papain-like cysteine protease that has specificity for amino terminal dipeptides. The enzyme plays a role in the activation of several pro-inflammatory serine proteases by removal of their aminoterminal inhibitory dipeptides. Genetic mutations that cause loss of cathepsin C activity in humans are associated with PAPILLON-LEFEVRE DISEASE.
ENDOPEPTIDASES which have a cysteine involved in the catalytic process. This group of enzymes is inactivated by CYSTEINE PROTEINASE INHIBITORS such as CYSTATINS and SULFHYDRYL REAGENTS.
A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured. Such rupture is supposed to be under metabolic (hormonal) control. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
A carboxypeptidase that catalyzes the release of a C-terminal amino acid with a broad specificity. It also plays a role in the LYSOSOMES by protecting BETA-GALACTOSIDASE and NEURAMINIDASE from degradation. It was formerly classified as EC 188.8.131.52 and EC 184.108.40.206.
N-acylated oligopeptides isolated from culture filtrates of Actinomycetes, which act specifically to inhibit acid proteases such as pepsin and renin.
A homologous group of endogenous CYSTEINE PROTEINASE INHIBITORS. The cystatins inhibit most CYSTEINE ENDOPEPTIDASES such as PAPAIN, and other peptidases which have a sulfhydryl group at the active site.
A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.
Cysteine Proteinase Inhibitors
Exogenous and endogenous compounds which inhibit CYSTEINE ENDOPEPTIDASES.
Any member of the group of ENDOPEPTIDASES containing at the active site a serine residue involved in catalysis.
Compounds which inhibit or antagonize biosynthesis or actions of proteases (ENDOPEPTIDASES).
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 220.127.116.11.
A subclass of peptide hydrolases that depend on a CYSTEINE residue for their activity.
A cytastin subtype found at high levels in the SKIN and in BLOOD CELLS. Cystatin A incorporates into the cornified cell envelope of stratified squamous epithelial cells and may play a role in bacteriostatic properties of skin.
An enzyme that catalyzes the hydrolysis of proteins, including elastin. It cleaves preferentially bonds at the carboxyl side of Ala and Val, with greater specificity for Ala. EC 18.104.22.168.
Amino Acid Sequence
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.
Rare, autosomal recessive disorder occurring between the first and fifth years of life. It is characterized by palmoplantar keratoderma with periodontitis followed by the premature shedding of both deciduous and permanent teeth. Mutations in the gene for CATHEPSIN C have been associated with this disease.
An extracellular cystatin subtype that is abundantly expressed in bodily fluids. It may play a role in the inhibition of interstitial CYSTEINE PROTEASES.
Hydrolases that specifically cleave the peptide bonds found in PROTEINS and PEPTIDES. Examples of sub-subclasses for this group include EXOPEPTIDASES and ENDOPEPTIDASES.