5.3.1.24 2,5-diamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one - 5.3.1.24 additional information the enzyme is essential for cell proliferation in the absence of tryptophan 5.3.1.24 N-(5-phospho-beta-D-ribosyl)anthranilate - 5.3.1.24 N-(5-phospho-beta-D-ribosyl)anthranilate fourth step in tryptophan biosynthesis 5.3.1.24 N-(5-phospho-beta-D-ribosyl)anthranilate third step in tryptophan biosynthesis 5.3.1.24 N-(5-phospho-beta-D-ribosyl)anthranilate involved in tryptophan biosynthesis from chorismate