These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.
Pubmed for Handhelds
PUBMED FOR HANDHELDS
Search MEDLINE/PubMed
Title: Use of endoproteases to identify catalytic domains, linker regions, and functional interactions in soluble peptidylglycine alpha-amidating monooxygenase. Author: Husten EJ, Tausk FA, Keutmann HT, Eipper BA. Journal: J Biol Chem; 1993 May 05; 268(13):9709-17. PubMed ID: 8486658. Abstract: The production of alpha-amidated peptides is accomplished through the sequential action of two enzymes, peptidylglycine alpha-hydroxylating monooxygenase (PHM) and peptidyl-alpha-hydroxyglycine alpha-amidating lyase (PAL), that are contained within the bifunctional peptidylglycine alpha-amidating monooxygenase (PAM) protein. Tissue-specific alternative splicing and endoproteolysis are known to generate both soluble and integral membrane mono- and bifunctional PAM proteins. In order to investigate the functional consequences of these differences we purified PAM-3, a soluble 95-kDa bifunctional form of the enzyme, from the spent medium of stably transfected hEK-293 cells. Using NH2-terminal sequence analysis of products of limited endoproteolysis and antibody cross-reactivity we identified protease-sensitive regions at the NH2 terminus, between the 35-kDa PHM and 42-kDa PAL domains and at the COOH terminus of the protein. Endoproteolytic removal of the COOH-terminal region from the bifunctional PAM-3 protein shifted the pH optimum of PHM to a more alkaline pH, increased the turnover number (kappa(cat)) of PHM and decreased its KM for alpha-N-acetyl-Tyr-Val-Gly; the catalytic properties of PAL were not altered. Since peptide amidation can be a rate-limiting step in the biosynthesis of neuropeptides, similar increases in PHM activity in vivo may play an important role in regulating the extent of peptide alpha-amidation.[Abstract] [Full Text] [Related] [New Search]