In HRP-based detection, which of the following is a common substrate used to generate a colorimetric signal?

In HRP-based detection, which of the following is a common substrate used to generate a colorimetric signal?

• A. Naphthol-AS-phosphate
• B. 3,3'-diaminobenzidine
• C. Tetramethylbenzidine
• D. Hydrogen peroxide

Answer: (D)

In HRP-based detection, the color you see comes from a chromogenic substrate that HRP oxidizes in the presence of hydrogen peroxide. Hydrogen peroxide is the oxidant that drives the reaction, not the color source. The most common color-producing substrates are 3,3'-diaminobenzidine (DAB) and tetramethylbenzidine (TMB), which yield brown and blue-to-yellow colors, respectively. Naphthol-AS-phosphate is used with alkaline phosphatase, not HRP. So the key idea is that a chromogenic substrate like DAB or TMB generates the color, with hydrogen peroxide simply enabling the reaction.

In HRP-based detection, the color you see comes from a chromogenic substrate that HRP oxidizes in the presence of hydrogen peroxide. Hydrogen peroxide is the oxidant that drives the reaction, not the color source. The most common color-producing substrates are 3,3'-diaminobenzidine (DAB) and tetramethylbenzidine (TMB), which yield brown and blue-to-yellow colors, respectively. Naphthol-AS-phosphate is used with alkaline phosphatase, not HRP. So the key idea is that a chromogenic substrate like DAB or TMB generates the color, with hydrogen peroxide simply enabling the reaction.