Liberation of an N-terminal proline-rich peptide from the cryptic proteinase of fibronectin by auto-proteolysis.
Fibronectin (Fn) is a modular glycoprotein present in both the extra-cellular matrix and blood plasma. It has a cryptic zinc-metalloproteinase activity (Fn-proteinase) in the gelatin-binding domain (GBD). The nature of the enzyme's substrates and the specificity of the peptide bonds cleaved are not yet precisely known. We used mass spectrometry to demonstrate the auto-proteolytic cleavage of Fn-proteinase. A 14-mer N-terminal peptide is the most important product released. This peptide has a very peculiar sequence, AAVYQPQPHPQPPP, demonstrating that Fn-proteinase cleaves after three consecutive proline residues.
Pagano
Maurice
M
Enzymologie Moléculaire et Fonctionnelle, FRE 2852, CNRS-University Paris 6 (UPMC), T43, 2 Place Jussieu, 75251 Paris Cedex 05, France. maurice.pagano@upmc.fr
Clodic
Gilles
G
Bolbach
Gérard
G
Michiel
Magalie
M
Haddag
Saliha
S
Reboud-Ravaux
Michèle
M
D000595:Amino Acid Sequence / Q000502:physiology; D000818:Animals; D002417:Cattle; D005353:Fibronectins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D045726:Metalloproteases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology
D005353:Fibronectins; D010455:Peptides; D045726:Metalloproteases