-!- This enzyme, involved in beta-L-colitose biosynthesis, is a unique vitamin-B6-dependent enzyme. -!- In the first step of catalysis, the bound pyridoxal phosphate (PLP) cafactor is transaminated to the pyridoxamine 5'-phosphate (PMP) form of vitamin B(6), using L-glutamate as the amino group donor. -!- The PMP cofactor then forms a Schiff base with the sugar substrate and the resulting adduct undergoes a 1,4-dehydration to eliminate the 3-OH group. -!- Hydrolysis of the product from the enzyme restores the PLP cofactor and results in the release of an unstable enamine intermediate. -!- This intermediate tautomerizes to form an imine form, which hydrolyzes spontaneously, releasing ammonia and forming the final product.