, 1-(2-carboxyphenylamino)-1-deoxy-D-ribulose-5-phosphate , and carboxy-lyase (cyclizing) . This enzyme participates in phenylalanine , tyrosine and tryptophan biosynthesis and two-component system - general. It employs one cofactor , pyruvate . [ edit ] Structural studies In some bacteria , IGPS is a single chain]] [[enzyme. In others, such as Escherichia coli ,