Bettie Sue Masters
Born	1937 (age 86–87) Lexington, Virginia
Alma mater	Roanoke College (B.S.) Duke University (Ph.D.)
Scientific career
Fields	Biochemistry
Thesis	The mechanism of hepatic microsomal triphosphopyridine nucleotide-cytochrome c reductase (1963)

Bettie Sue Siler Masters is an adjunct professor at Duke University known for her work on nitric oxide synthase and cytochrome P450 reductase. She was the 1992 recipient of the FASEB Excellence in Science Award, and has been elected as a member of the National Academy of Medicine and as a fellow of the American Association for the Advancement of Science.^[1]

Masters was born in Lexington, Virginia, where her father was a radio announcer and a singer. As a child she was an avid reader of Sherlock Holmes and Dr. Watson whose analytical skills she admired.^[2] She became interested in chemistry during her sophomore year in high school, and placed high enough in the Westinghouse Science Talent Search to receive a scholarship for college. After the College of William & Mary would not accept the scholarship because she was a woman, she went on to attend Roanoke College, thereby becoming a first-generation college student.^[2] She graduated from Roanoke College in 1959 with a B.S. in chemistry.^[3] In 1963, she earned her Ph.D. in biochemistry from Duke University.^[4]

Following her Ph.D. work, she conducted postdoctoral research first with fellowship support from the American Cancer Society and then with grant support from the American Heart Association.^[3][2] In 1968, she moved to the University of Texas Southwestern Medical School where she started her research lab.^[3][5] In 1982, she moved to the Medical College of Wisconsin to accept the position as chair of the department of biochemistry, thereby becoming the first woman to hold this position.^[3] In 1990, she moved to the University of Texas Health Science Center at San Antonio where she was named as the Robert A. Welch Distinguished Professor in Chemistry.^[3] As of 2022, she is an adjunct professor at Duke University in the department of biochemistry.^[5]

Masters is known for her work on the structure and function of enzymes. As a graduate student she characterized cytochrome P450 reductase (NADPH-cytochrome P450 oxidoreductase).^[6][7] She went on to develop methods to purify enzymes, such as cytochrome P450 reductase, which allows investigation into their biochemical properties^[8] and identification of the active sites of the protein through x-ray crystallography.^[9] Concerning nitric oxide synthase, she examined the atomic structure of the endothelial isoenzyme, the zinc bound within the protein, and the co-factors required (heme and tetrahydrobiopterin).^[10][11]

• Vásquez-Vivar, Jeannette; Kalyanaraman, B.; Martásek, Pavel; Hogg, Neil; Masters, Bettie Sue Siler; Karoui, Hakim; Tordo, Paul; Pritchard, Kirkwood A. (1998-08-04). "Superoxide generation by endothelial nitric oxide synthase: The influence of cofactors". Proceedings of the National Academy of Sciences. 95 (16): 9220–9225. Bibcode:1998PNAS...95.9220V. doi:10.1073/pnas.95.16.9220. ISSN 0027-8424. PMC 21319. PMID 9689061.
• Roman, L J; Sheta, E A; Martasek, P; Gross, S S; Liu, Q; Masters, B S (1995-08-29). "High-level expression of functional rat neuronal nitric oxide synthase in Escherichia coli". Proceedings of the National Academy of Sciences. 92 (18): 8428–8432. Bibcode:1995PNAS...92.8428R. doi:10.1073/pnas.92.18.8428. ISSN 0027-8424. PMC 41170. PMID 7545302.
• McMillan, K; Bredt, D S; Hirsch, D J; Snyder, S H; Clark, J E; Masters, B S (1992). "Cloned, expressed rat cerebellar nitric oxide synthase contains stoichiometric amounts of heme, which binds carbon monoxide". Proceedings of the National Academy of Sciences. 89 (23): 11141–11145. Bibcode:1992PNAS...8911141M. doi:10.1073/pnas.89.23.11141. ISSN 0027-8424. PMC 50505. PMID 1280819.
• Yasukochi, Y; Masters, B S (1976). "Some properties of a detergent-solubilized NADPH-cytochrome c(cytochrome P-450) reductase purified by biospecific affinity chromatography". Journal of Biological Chemistry. 251 (17): 5337–5344. doi:10.1016/s0021-9258(17)33166-6. ISSN 0021-9258. PMID 821951.

Masters has received numerous honors and awards from Roanoke College, her alma mater. In 1973, she was awarded the Roanoke College Medal for her distinguished service to her community and her profession.^[3] In 1983, she received an Honorary Doctor of Science degree from Roanoke College.^[3]

In 1990, Masters was recruited to the University of Texas Health Science Center at San Antonio as the first Robert A. Welch Distinguished Professor in Chemistry.^[3] In 1992, Masters received the Excellence in Science Award from the Federation of American Societies for Experimental Biology (FASEB). In 2000, she was the recipient of the Bernard B. Brodie Award in Drug Metabolism from the American Society for Pharmacology and Experimental Therapeutics.^[12] In 1996, Masters was elected as a member of the National Academy of Medicine^[13] and, in 2001, she was elected as a fellow of the American Association for the Advancement of Science.^[3][14] In 2005, Charles University (Prague) awarded Masters an honorary degree, Doctorem Medicinae Honoris Causae, in recognition of her work.^[2] In 2022, the Medical College of Wisconsin (MCW) awarded Masters an Honorary Doctor of Science degree in recognition of her leadership role in the field of biochemistry and her contributions to medical scientist training (via initiation of MCW's MD/PhD training program--Medical Scientist Training Program).^[15][16]