Arabidopsis det 2 Is Defective in the Conversion of ( 24 R )-24-Methylcholest-4-En-3-One to ( 24 R )-24-Methyl-5 a-Cholestan-3-One in Brassinosteroid Biosynthesis 1

The Institute of Physical and Chemical Research (RIKEN), Wako-shi, Saitama 351–0198, Japan (T.N., S.F., A.S., S.Y.); Tama Biochemical Co., Ltd., Shinjuku-ku, Tokyo 163–0704, Japan (T.N.); Department of Chemistry, Joetsu University of Education, Joetsu-shi, Niigata 943–8512, Japan (S.T.); and Plant Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037 (J.L., J.C.)