substrat chromogène

CONT: Dans ce cas, les dNTP (2-désoxyribonucléotides triphosphates peuvent être marqués par la biotine [...] Les produits d'amplification sont ensuite détectés directement par l'avidine ou la streptavidine couplée à la phosphatase alcaline ou à la peroxydase et le substrat chromogène correspondant.

CONT: The Bartels PRIMA SystemTM Cytomegalovirus IgM Enzyme Immunoassay is a rapid, qualitative method for the detection of IgM Antibody to cytomegalovirus in human serum. Patient serum is diluted with specimen diluent that contains an absorbent to remove IgG. The absorbent prevents IgG/rheumatoid factor complexes from forming and prevents interfering competition from IgG during the test procedure. The treated serum is incubated with purified CMV antigens bound to EIA plate wells. If antibodies to CMV are present, they bind to the antigen and do not rinse off. Subsequently, when enzyme labeled anti-human IgM is added to the reaction site, it binds to the immobilized antibodies. After washing and the addition of a chromogenic substrate and stop solution, specimens containing antibodies to CMV produce a color endpoint reaction which is measured and compared to negative and positive controls, and may be measured spectrophotometrically.

CONT: Quando o vetor está intacto (não recombinante), a enzima é funcional e frente ao substrato cromogênico este é clivado produzindo placas de cor azul. Por outro lado, quando um fragmento de DNA é inserido no múltiplo sitio de clonagem, a expressão da enzima é suprimida, portanto as células são incapazes de metabolizar o substrato cromogênico formando placas incolores.