Evaluation of protein assay methods for pollen and fungal spore extracts

The usual procedures available for protein estimation of biological extracts often give variable results due to presence of many peptides and coloured materials. To identify a suitable method for allergenic extracts, protein was estimated from common pollen and fungal antigens by modified Lowry's (ML), Bradford (B), micro-Kjeldahl (MK), Bicinchoninic acid (BCA) and modified BCA (MBCA) assays. Bradford assay resulted in low protein values, whereas BCA method gave very high values in general. Statistical analysis of the results revealed similarity between protein values quantitated by MK, ML and MBCA methods for most of the extracts. Graded volumes of the extracts on subjecting to protein estimation by these three methods showed linear response, while recovery of a protein (bovine serum albumin) added to the extracts was greater than 90%.