A NOVEL PROTEIN ASSAY-METHOD USING TETRAPHENYLPORPHIN TETRASULFONATE (TPPS4)

A sensitive protein assay method which involves the reaction of TPPS4 with protein is described. When protein is added to TPPS4 solution, an absorption band with the maximum at 488 nm appears and the absorbance is proportional to the concentration of protein. Just Like the Soret absorption of the porphyrin, the new band is very narrow and there is no overlap at all between them, which means the free dyes would not give any background for the detection of the protein-TPPS4 complexes. A new spectrophotometric method for determination of protein has been constructed and applied to the determination of human plasma protein and urinary protein; The assay using microtiter plates has also been studied.