Institut National De La Sante Et De La Recherche Medicale

Bernard Descomps

Beatrice Terouanne

Jean-Claude Nicolas

Andre C De Paulet

Jean C Nicolas

Andre Crastes De Paulet

The invention relates to a method for the selective separation of a given protein substance having an affinity for a ligand from other substances some of them having the same affinity for the ligand but also having a high molecular weight, higher than that of said protein substance, said substances being in solution. The method consists of filtering said substances on a gel which excludes said high molecular weight substances, said gel being coupled with a ligand for which said protein substance has affinity. The method may be applied to enzymatic and especially to immunoenzymatic assays.

Method for the separation of a protein substance from a solution

The invention relates to a novel enzymatic labelling agent for immunoenzymatic assays. The labelling agent is .DELTA..sub.5, 3-keto-steroid isomerase. The enzymatic activity bound to the antibody can be revealed advantageously by: (1) direct reading on the supernatent liquor or on the cake obtained by precipitation by means of a solvent, such as polyethylene glycol, with the use of soluble antibodies; (2) reading in solution after liberation of the enzyme from the antigen-antibody complex by a reducing agent, such as dithiotreitol; (3) immediate reading after filtration of a substrate solution on the insolubilized antibody-antigen-enzyme complex. The method can be used for immunoenzymatic assays automatically on substances present in very low concentrations, such as hypophysial hormones and plasmatic steroids.

Growing community of inventors

Montpellier, France

Bernard Descomps