tailieunhanh - Báo cáo khoa học: Discriminating between the activities of human cathepsin G and chymase using fluorogenic substrates

Cathepsin G (CG) (EC ) and chymase (EC ) are two clo-sely-related chymotrypsin-like proteases that are released from cytoplasmic granules of activated mast cells and⁄or neutrophils. We investigated the potential for their substrate-binding subsites to discriminate between their substrate specificities, aiming to better understand their respective role dur-ing the progression of inflammatory diseases. | IFEBS Journal Discriminating between the activities of human cathepsin G and chymase using fluorogenic substrates Brice Korkmaz1 2 Gwenhael Jegot1 2 Laurie C. Lau3 Michael Thorpe4 Elodie Pitois1 2 Luiz Juliano5 Andrew F. Walls3 Lars Hellman4 and Francis Gauthier1 2 1 Unite INSERM U-618 Proteases et Vectorisation pulmonaires Tours France 2 Universite Francois Rabelais de Tours France 3 Immunopharmacology Group Sir Henry Wellcome Laboratories Southampton General Hospital UK 4 Department of Celland Molecular Biology The BiomedicalCenter Uppsala University Sweden 5 Departamento de Biofisica Escola Paulista de Medicina Universidade Federal Sao Paulo Brazil Keywords cathepsin G chymase FRET substrate kinetics mast cell serine protease Correspondence B. Korkmaz Unite INSERM U-618 Proteases et Vectorisation pulmonaires Universite Francois Rabelais de Tours 37032 Tours France Fax 33 2 47 36 60 46 Tel 33 2 47 36 62 53 E-mail Received 4 April 2010 revised 11 May 2011 accepted 16 May 2011 doi Cathepsin G CG EC and chymase EC are two closely-related chymotrypsin-like proteases that are released from cytoplasmic granules of activated mast cells and or neutrophils. We investigated the potential for their substrate-binding subsites to discriminate between their substrate specificities aiming to better understand their respective role during the progression of inflammatory diseases. In addition to their preference for large aromatic residues at P1 both preferentially accommodate small hydrophilic residues at the ST subsite. Despite significant structural differences in the S2 subsite both prefer an acidic residue at that position. The Ala226 Glu substitution at the bottom of the CG S1 pocket which allows CG but not chymase to accommodate a Lys residue at P1 is the main structural difference allowing discrimination between the activities of these two proteases. However a Lys at P1 is accommodated much less