Publication Details (including relevant citation information):
ANALYTICAL BIOCHEMISTRY, 417(1), 156-8, 2011
This study revealed a major interference from sulfo-N-hydroxysuccinimide (sulfo-NHS) in the bicinchoninic acid (BCA) protein assay. Sulfo-NHS, a common reagent used in bioconjugation and analytical biochemistry, exhibited absorbance signals and absorbance peaks at 562 nm, comparable to bovine serum albumin (BSA). However, the combined absorbance of sulfo-NHS and BSA was not strictly additive. The sulfo-NHS interference was suggested to be caused by the reduction of Cu2+ in the BCA Kit’s reagent B (4% cupric sulfate) in a manner similar to that of the protein.