Reversible dissociation of a tumor-cell surface protease-inhibitor complex

Tumour cell surfaces possess a cell surface protease (GB), which can be recognised by a cytoplasmic inhibitor protein prepared from cultured tumour cells. This enzyme inhibitor complex has been shown to be reversibly dissociated by 10-(4)M sodium dodecyl sulphate. Sections of frozen tumour tissue were used to provide cells with active GB and the successful recognition and inhibition of this GB was followed by fluorescence microscopy employing the competitive inhibitor 9-amino acridine as a fluorescent probe.