Affiliation: | Biophysics Research Division, Institute of Science and Technology, University of Michigan, Ann Arbor, Mich. 48105 U.S.A.; Department of Biochemistry, University of Illinois, Urbana, Ill. 61801 U.S.A.; Department of Biochemistry and the Institute for Enzyme Research, University of Wisconsin, Madison, Wisc. 53706 U.S.A. |