Cresol Red





Cresol red is a pH indicator and molecular weight marker for agarose gels. Unlike bromophenol blue and xylene cyanol, cresol red does not inhibit Taq polymerase in PCRs.

Agarose molecular weight marker
advantage: much less shadow on EtBr pictures unlike xylene cyanol and bromophenol blue


 * molecular weight 404 g/mol
 * in 1% agarose at ~1000 bp (between xylene cyanol 5000bp and bromophenol blue 500bp)
 * in 3% agarose at >100bp (xylene cyanol 300bp)

pH indicator

 * amber - acidic pH
 * yellow - neutral
 * red - alkaline