Carboxypeptidases

Part of speech: noun

Definitions

1. Enzymes that break peptide bonds by removing amino acids one at a time from the carboxyl terminus of a protein chain
2. Digestive proteases that split off terminal amino acids at the carboxyl end of polypeptides, aiding protein breakdown
3. Catalysts that hydrolyze the final peptide bond at the carboxyl terminal of proteins, releasing single amino acid residues

Etymology: Carboxypeptidases are a family of enzymes, and the word is built the way modern scientific names usually are: from parts that each carry a precise chemical meaning. "Carboxy-" refers to the carboxyl group (COOH) found at the end of a protein chain, "peptide" refers to the short chains of amino acids linked by peptide bonds, and "-ase" is the suffix that marks a substance as an enzyme. Put together, the name describes an enzyme that cuts peptides from the carboxyl end of a chain, which is exactly what these enzymes do. The plural simply adds an "s" to the singular "carboxypeptidase", which is the form used when referring to more than one of these enzymes or to the family as a whole.