Bernhard Witkop

Bernhard Witkop, 93, a renowned organic chemist at the National Institutes of Health, died of congestive heart failure on Nov. 22, 2010, at home in Chevy Chase, Md.

Born in Freiburg, Germany, Witkop received a doctorate in organic chemistry from the University of Munich in 1940 under chemistry Nobel Laureate Heinrich Wieland, who shielded Witkop from Nazi persecution.

Witkop immigrated to the U.S. in 1947 and taught at Harvard University before joining NIH in Bethesda, Md., in 1950. Witkop was a major force behind the synthesis and characterization of natural products, such as antibiotics and neurotoxins from plant and animal sources. He developed routes to nonenzymatic cleavage of peptides at specific amino acids, including the widely used cyanogen bromide method. That work later enabled commercial production of insulin.

Witkop published many papers, including “Forty Years of Trypto-fun,” an article about indole chemistry that summarized a large part of his life’s work (Heterocycles, DOI: 10.3987/R-1983-10-2059).

In the early 1960s, Witkop and NIH colleagues including Sidney Udenfriend and Herbert Weissbach identified tryptophan hydroxylase, which is involved in the first step in serotonin biosynthesis. Subsequently, they discovered the NIH shift, a chemical rearrangement in which hydrogen migrates around an aromatic ring during hydroxylation. It has been a key process in the development of many therapies and in the study of carcinogenesis.

In addition, Witkop initiated the NIH foreign scientists training program and began studying classical Japanese at age 40, later lecturing in that language. In recognition of Witkop’s efforts in scientific exchange, the emperor conferred on Witkop Japan’s Order of the Sacred Treasure.

After retiring in 1987 as chief of the Laboratory of Chemistry at NIH’s National Institute of Diabetes & Digestive & Kidney Diseases, he became an Institute Scholar. He was elected to the National Academy of Sciences and was an emeritus member of ACS, joining in 1948.

Witkop is survived by his wife of 65 years, Marlene; daughters Cornelia Hess and Phyllis Kasper; and son, Thomas.