Abstract: A composition for enzyme immunoassay using immunofluorescence comprises (i) a fluorogenic enzymatic substrate and (ii) a quenched fluorogenic compound that forms a fluorescent compound after hydrolysis of the fluorogenic enzymatic substrate. The composition may be useful for performing a method for in vitro detection and/or quantification of an analyte of a liquid test sample liable to contain the analyte.

Abstract: A composition for enzyme immunoassay using immunofluorescence comprises (i) a fluorogenic enzymatic substrate and (ii) a quenched fluorogenic compound that forms a fluorescent compound after hydrolysis of the fluorogenic enzymatic substrate. The composition may be useful for performing a method for in vitro detection and/or quantification of an analyte of a liquid test sample liable to contain the analyte.

Abstract: A method is described for detecting the gamma-glutamyl transferase enzyme isoforms (GGT, EC 2.3.2.2) in a sample of biological fluid, such as for example plasma or serum. The method comprises an HPLC separation step of the sample proteins based on the molecular size and a second step for detecting the GGT isoforms by post-column reaction with a GGT enzyme substrate capable of generating a detectable final product, preferably by spectrophotometric or fluorimetric means. The GGT isoforms can be separated by ultra-centrifugation, thereby obtaining three enzymatic isoforms characterized by molecular weights of approximately 2000, 940, and 140 KDa, respectively.

Abstract: A process for determining S-nitrosothiols, in particular S-nitrosoglutathione, in biological fluids that is easy, selective, cheap with respect to the prior art, which requires the use of equipment commonly available in laboratories, at low cost, which can be used by not qualified operators. The process is based on the hydrolysis of S-nitrosoglutathione (GSNO) by an enzyme, in particular ?-glutamyltranspeptidase (GGT). This enzyme hydrolizes the residual ?-glutamyl of GSNO for giving glutamate (GIu) and S-nitroso-cysteinylglycine (GIyCySNO). In the presence of ions of transition metals GGT speeds up the release of NO since the intermediate that is formed, the GIyCySNO, is much more sensitive to a metal-dependent decomposition. Advantageously, the amount of nitric oxide present in the sample is measured through a reaction thereof with 4,5 diaminof luorescein (DAF-2), said reaction creating a fluorescent compound in an amount proportional to the S-nitrosothiol amount present in the sample.

Abstract: A method is described for detecting the gamma-glutamyl transferase enzyme isoforms (GGT, EC 2.3.2.2) in a sample of biological fluid, such as for example plasma or serum. The method comprises an HPLC separation step of the sample proteins based on the molecular size and a second step for detecting the GGT isoforms by post-column reaction with a GGT enzyme substrate capable of generating a detectable final product, preferably by spectrophotometric or fluorimetric means. The GGT isoforms can be separated by ultra-centrifugation, thereby obtaining three enzymatic isoforms characterised by molecular weights of approximately 2000, 940, and 140 KDa, respectively.

Abstract: A process for determining S-nitrosothiols, in particular S-nitrosoglutathione, in biological fluids that is easy, selective, cheap with respect to the prior art, which requires the use of equipment commonly available in laboratories, at low cost, which can be used by not qualified operators. The process is based on the hydrolysis of S-nitrosoglutathione (GSNO) by an enzyme, in particular ?-glutamyltranspeptidase (GGT). This enzyme hydrolizes the residual 7-glutamyl of GSNO for giving glutamate (GIu) and S-nitroso-cysteinylglycine (GIyCySNO). In the presence of ions of transition metals GGT speeds up the release of NO since the intermediate that is formed, the GIyCySNO, is is much more sensitive to a metal-dependent decomposition. Advantageously, the amount of nitric oxide present in the sample is measured through a reaction thereof with 4,5 diaminof luorescein (DAF-2), said reaction creating a fluorescent compound in an amount proportional to the S-nitrosothiol amount present in the sample.