The standard curve with HRP-301-16 in direct competitive ELISA.The 0.5 µg/ml of SAH coating standard (Cat # ACT00302 Lot # ACP420210) was coated on micro-titer wells.Serial dilution of SAH standard (Cat # AST00301) was added along with 1 :1,000 diluted HRP-301-16 and was incubated for about 60 minutes.The substrates were then added and OD450 was measured.