Carboxypeptidases


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Related to Carboxypeptidases: Carboxypeptidase B

Carboxypeptidases

 

an enzyme group of the hydrolase class (carboxypeptidase-A, carboxypeptidase-B, and yeast car-boxypeptidase) that catalyze the stepped hydrolysis of polypeptides from the C-end, that is, from the amino acid that contains a free carboxyl group (—COOH). The molecular weight of car-boxypeptidases exceeds 34, 000. Carboxypeptidase-A is most active on aromatic amino acids; carboxypeptidase-B, on lysine or arginene; and yeast carboxypeptidase, on glycine or lysine. In addition, carboxypeptidases have esterase activity (the ability to split ether bonds). Carboxypeptidase-A enters the duodenum from the pancreas where it is produced in the form of inactive procarboxypeptidase-A, which becomes carboxypeptidase-A, primarily under the influence of trypsin.

REFERENCES

Dixon, M., and E. Webb. Fermenty. Moscow, 1966. (Translated from English.)
Mosolov, V. V. Proteoliticheskie fermenty. Moscow, 1971.
References in periodicals archive ?
The exceptions were extracellular proteins, such as serine carboxypeptidase, thaumatin-like protein, acid [alpha]- and [beta]-galactosidase, peroxidase, as well as [alpha]-xylosidase.
Determination of pancreatic carboxypeptidase A in human blood serum.
Measuring carboxypeptidase A activity with a centrifugal analyzer: analytical and clinical considerations.
A unique activity assay for carboxypeptidase A in human serum.
Determination of carboxypeptidase A using N-acetyl-phenylalanyl-3-thiaphenylalanine as substrate: application to a direct serum assay.
Carboxypeptidase U (CPU, (1) activated thrombin-activable fibrinolysis inhibitor; EC 3.
Another important advantage of activity assays compared with antigen assays is that the 2 described polymorphisms in the coding region of proCPU (Thr147A1a and Thr325I1e) have similar activation kinetics and the activated enzymes have similar carboxypeptidase B-like activity toward small synthetic substrates (26, 28).
Typical assays for carboxypeptidase activity rely on a change of absorbance, and sensitivity is always an important issue.
The most important advantage of activity assays compared with antigen assays is that the 2 described polymorphisms in the coding region of proCPU (Thr147A1a and Thr325I1e) have similar activation kinetics and the activated enzymes have similar carboxypeptidase B-like activity toward small synthetic substrates (26, 28).
We first reported in 1988 on the presence of a labile carboxypeptidase activity in fresh human serum that interfered with the assay of CPN (1-3).
Inactivated serum--serum in which neither activatable proCPU nor basic carboxypeptidase activity could be detected--was prepared by incubating human serum for 12 h at 56 [degrees]C.
2]-terminal sequencing reveal the sequence FQSGQV-LAALPRTSRQVQVL, which confirmed its identity as plasma carboxypeptidase B (7).