Julius Rebek, Jr. is a Hungarian-born American chemist and expert on molecular self-assembly.
Rebek was born in Beregszasz, Ukraine, which at the time was part of Hungary, in 1944 and lived in Austria from 1945 to 1949. In 1949 he and his family immigrated to the United States and settled in Kansas. Rebek graduated from the University of Kansas with a Bachelor of Arts degree in chemistry. Rebek received his Master of Arts degree and his Ph.D. in organic chemistry from the Massachusetts Institute of Technology in 1970. There he studied peptides under D.S. Kemp.
Rebek was an assistant professor at the University of California at Los Angeles from 1970 to 1976. There he developed the three-phase test for reactive intermediates. In 1976, he moved to the University of Pittsburgh, where he developed cleft-like structures for studies in molecular recognition. In 1989 he returned to MIT, where he became the Camille Dreyfus Professor of Chemistry and devised synthetic, self-replicating molecules. In July 1996, he moved his research group to the Scripps Research Institute to become the director of the Skaggs Institute for Chemical Biology, where he continues to work in molecular recognition and self-assembling systems.