PRE-STAINED 3,3',5,5'-TETRAMETHYLBENZIDINE SUBSTRATES FOR THE DETECTION OF ENZYME ACTIVITY

摘要

The present invention relates to storage-stable pre-stained 3,3',5,5'-tetramethylbenzidine (TMB) substrates comprising: (a) a water-based TMB substrate composition which includes a peroxide (e.g. hydrogen peroxide or urea hydrogen peroxide) and (b) a dye which is soluble therein. Suitable dyes to be included in the substrate preferably have an absorbance at 450 nm of at the most 100 milli absorbance units. Examples of dyes are Phloxine B, Eosin B and Quinaldine Red. The substrates are advantageous in that they include a dye which is visible to the human eye. This is especially valuable when the substrates are handled and measured. The substrates are especially suitable for enzyme assays such as enzyme-linked-immunosorbent-assays (ELISA), e.g. horse radish peroxidase (HRP) is used. The substrates may advantageously include less than 5 % organic solvents and a solubility increasing agent such as polyvinylalcohol. The substrates are storage-stable for more than 12 months.