Reaction of erythrosin B with proteins results in a stable, highly col
ored chromophore with an absorbance maximum at 545 nm. This is the bas
is for a new quantitative determination method of proteins in solution
. The assay can be performed at room temperature, but is faster and mo
re sensitive at 90-95 degrees C. The erythrosin assay is characterized
by (i) stable dye-protein color, (ii) high sensitivity (2-14 mu g/ml
protein), (iii) short reaction time (1.5-2 min at 90-95 degrees C), (i
v) good reproducibility, (v) limited interference by common reagents,
and (vi) low protein-to-protein variability. Thus, the erythrosin assa
y can be useful for routine analytical purposes and may overcome some
of the limitations of other currently employed assays. (c) 1994 Academ
ic Press, Inc.