Bettie Sue Siler Masters was born in Lexington, Virginia. In high school she won a Westinghouse Science Talent Search competition that allowed her to obtain a science scholarship to Roanoke College. She was awarded her Ph.D. in biochemistry from Duke University in 1963 and continued her training there as a postdoctoral fellow. In 1968, Masters received an established investigatorship from the American Heart Association, and began her academic career at the University of Texas Southwestern Medical Center in Dallas. There, she became a full professor in 1976, but left in 1982 to become chair of Biochemistry at the Medical College of Wisconsin. She was then recruited to the University of Texas Health Science Center in San Antonio as the first Robert A. Welch Distinguished Professor in Chemistry in 1990.
Masters’ research centers on the structure-function relationships of flavoproteins and heme proteins involved in major monooxygenation pathways. These include a gene subfamily of the cytochromes P450, heme proteins that function in the hydroxylation of fatty acids and prostaglandins and are responsible for vasoconstrictive effects in the lung and kidney, and the three genetically coded forms of nitric oxide synthases (NOSs), neuronal, endothelial, and inducible, which produce NO as a signaling molecule. Utilizing a variety of biophysical techniques, Masters’ laboratory discovered that heme (iron protoporphyrin IX) is the oxygenation site for the NOS enzymes and, determined that a single zinc tetrathiolate occurs in the dimer interface of each of these proteins.
Masters received the Federation of American Societies for Experimental Biology Excellence in Science Award in 1992 and the American Society for Pharmacology and Experimental Therapeutics Bernard B. Brodie Award in 2000, and she served on the advisory committee to the Director of the National Institutes of Health from 2001 to 2004. She was president of the American Society for Biochemistry and Molecular Biology from 2002 to 2004. She was elected to the Institute of Medicine of the National Academies in 1996 and was elected a fellow of the American Association for the Advancement of Science in 2001.