The inhibitor reacting with a tumour cell surface protease can be exchanged with plasminogen activator inhibitor (PAI-1).
Tumour cells possess the cell surface protease guanidinobenzoatase (GB) which can be located by the fluorescent probe 9-amino acridine (9-AA). Frozen sections and formaldehyde fixed sections of tumour tissue were used to demonstrate the interactions between GB, 9-AA and two protein inhibitors of GB. A cytoplasmic extract from the tumour tissue, and a purified inhibitor of plasminogen activator (PAI-1) were shown to be exchangeable components of the enzyme-inhibitor complex on the fixed tumour cell surfaces. The evidence suggests that GB is functionally very similar to plasminogen activator and that this enzyme can be regulated by protein inhibitors in vivo and also by changes in the redox potential at the cell surface.
Steven
F S
FS
Department of Biochemistry and Molecular Biology, School of Biological Sciences, University of Manchester, UK.
Booth
N A
NA
D000585:Aminacrine; D002265:Carboxylic Ester Hydrolases / Q000037:antagonists & inhibitors*; D002462:Cell Membrane / Q000201:enzymology*; D003110:Colonic Neoplasms / Q000201:enzymology* / Q000473:pathology; D010450:Endopeptidases; D005456:Fluorescent Dyes; D006651:Histocytochemistry; D006801:Humans; D015849:Plasminogen Inactivators / Q000494:pharmacology*; D011480:Protease Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology
D005456:Fluorescent Dyes; D015849:Plasminogen Inactivators; D011480:Protease Inhibitors; D000585:Aminacrine; D002265:Carboxylic Ester Hydrolases; C037288:guanidinobenzoate esterase; D010450:Endopeptidases