Soil protease participates in the transformation of amino acids, proteins, and other protein‑nitrogen organic compounds present in soil. Its hydrolysis products serve as one of the nitrogen sources for higher plants. S-ALPT catalyzes protein hydrolysis under alkaline conditions and is associated with soil organic matter content, nitrogen levels, and other soil properties.
Determination principle: Under alkaline conditions, tyrosine reduces the phosphomolybdic acid compound to form tungsten blue, which has a characteristic absorption peak at 680 nm.