Medicago AB Products Are Available Worldwide. For Research Use Only. Specifically developed for immnoassay procedures. Ideal for phosphate-based ELISA methods. Also used as a chromogenic non-specific substrate in alkaline and acid phosphatase assays. Its soluble end-product is yellow and can be spectrophotometrically read at 405 to 410 nm. The reaction may be stopped with 3 M NaOH The substrate is more than 99% pure. Supplied in convenient exactly pre-weighed tablets containing 5 mg or 20 mg of substrate.