- Structural and mechanistic characteristics of dihydropteridine reductase: a member of the Tyr-(Xaa)3-Lys-containing family of reductases and dehydrogenases. Varughese, K.I., Xuong, N.H., Kiefer, P.M., Matthews, D.A., Whiteley, J.M. Proc. Natl. Acad. Sci. U.S.A. (1994)