protein C-terminal methylesterase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: C-terminal protein amino acid methyl ester + H2O = protein amino acid + methanol. [PMID:10318862, PMID:8650216]

C-terminal methylesterase activity is a molecular function that describes the ability of an enzyme to remove a methyl group from the carboxyl-terminal end of a protein or peptide. This type of enzymatic activity is crucial for a variety of cellular processes, including protein maturation, signal transduction, and regulation of protein function.

C-terminal methylesterases typically employ a catalytic mechanism involving the formation of a covalent intermediate between the enzyme and the substrate. This intermediate allows for the transfer of the methyl group from the substrate to a nucleophile within the active site of the enzyme, leading to the release of a demethylated protein and a methylated enzyme. The methyl group is then often removed from the enzyme through hydrolysis, regenerating the active site.

Specific examples of proteins with C-terminal methylesterase activity include:

- **Peptidyl-glycine alpha-amidating monooxygenase (PAM):** This enzyme plays a critical role in the biosynthesis of neuropeptides and hormones by catalyzing the amidation of glycine residues at the C-terminus of peptides. PAM also exhibits C-terminal methylesterase activity, which is thought to be involved in regulating the levels of amidated peptides.
- **Carboxypeptidase E (CPE):** This enzyme is involved in the processing of neuropeptides and hormones by removing C-terminal amino acids. CPE also exhibits C-terminal methylesterase activity, which may play a role in regulating the activity of other enzymes involved in peptide processing.
- **Methionine aminopeptidase (MetAP):** This enzyme removes the N-terminal methionine residue from newly synthesized proteins. MetAP also has C-terminal methylesterase activity, which may be involved in regulating the activity of other enzymes involved in protein processing.

The removal of C-terminal methyl groups can have significant effects on protein function. For instance, methylation can influence the stability, conformation, and interactions of proteins. The removal of these methyl groups can alter these properties, leading to changes in protein activity, localization, and degradation.

C-terminal methylesterase activity is an important molecular function that plays a critical role in a variety of cellular processes. Understanding the mechanisms and regulation of this activity is essential for elucidating the complex roles of proteins in cellular function and disease.'
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Proteins (2)

Compounds (1)