Catalysis of the hydrolysis of internal, alpha-peptide bonds in a polypeptide chain by a catalytic mechanism that involves a catalytic triad consisting of a serine nucleophile that is activated by a proton relay involving an acidic residue (e.g. aspartate or glutamate) and a basic residue (usually histidine).
The whole of the physical, chemical, and biochemical processes carried out by multicellular organisms to break down ingested nutrients into components that may be easily absorbed and directed into metabolism.
J. Biol. Chem. 272, 8099-8104 (1997)[PubMed:9065485]
The gene of a novel chymotrypsin-like serine protease has been cloned from human pancreas. The chymotrypsin-like enzyme-1 gene is located on chromosome 16q22.1 in a tight cluster with four unrelated genes. The gene has seven exons with the signal and activation peptide and the three main catalytic residues forming the active site encoded by separate exons. Northern blots of pancreatic mRNA showed a major transcript of 1.0 kilobases and a minor transcript of 1.3 kilobases due to alternative polyadenylation. No transcript was found in other tissues. Its presence in pancreatic tissue, duodenal juice, and urine was demonstrated with antisera raised against synthetic peptides from the derived amino acid sequence of the gene. The peptide sequences were chosen for being most dissimilar to chymotrypsin, and the antisera obtained did not react with purified human chymotrypsin. The proteolytically active CTRL-1 has been identified in pancreatic homogenate, duodenal juice, and urine, and a recombinant CTRL-1 has been characterized. Increased pancreatic secretion of CTRL-1 was induced by protease inhibitors indicating that the enzyme is secreted from pancreas upon feedback stimulation. Both native and recombinant CTRL-1 displayed chymotrypsin- and elastase-2-like activities and hydrolyzed the amide bonds of substrates having tyrosine, phenylalanine, or leucine residues at the P1 position. The enzyme was active over a broad pH range (6.5-9. 0), with a maximum at pH 8.0-8.5. CTRL-1 was produced as a zymogen of 264 amino acids as deduced from the gene sequence, with a sequence identity of 54% with human chymotrypsin B. The number and location of intron/exon junctions as well as the sequence similarity to chymotrypsin both at the DNA and protein level and the presence in duodenal juice indicate that this is a novel digestive enzyme of the chymotrypsin superfamily, albeit one with distinct physiological and biochemical features.
Enzyme which catalyzes hydrolysis reaction, i.e. the addition of the hydrogen and hydroxyl ions of water to a molecule with its consequent splitting into two or more simpler molecules.
Proteolytic enzyme with a serine residue (Ser) in its active site. The reactivity of the serine residue is ensured by the vicinity of a histidine and an aspartate residue (catalytic triad), all three residues are required for the charge relay system to take place.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.
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