as the alpha subunit binds to the beta 2 subunit , the tryptophan residue , which is within 2.2 nm of the active site of the beta 2 subunit , probably rotates with respect to the plane of the ring of the coenzyme , such that fluorescence energy transfer from tryptophan to pyridoxal phosphate is greatly reduced .
C0009235
coenzyme
C0034266
pyridoxal phosphate