Science, Tech, Math › Science Mercapto Group Definition Share Flipboard Email Print The left-hand side of this chemical group (cysteine) is a mercapto group. Todd Helmenstine Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Anne Marie Helmenstine, Ph.D. Facebook Twitter Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. Learn about our Editorial Process Updated on March 24, 2019 Definition: A mercapto group is a fuctional group containing a sulfur atom bonded to a hydrogen atom. General formula: -SH Also Known As: thiol group, sulfanyl group Examples: The amino acid cysteine contains a mercapto group. Cite this Article Format mla apa chicago Your Citation Helmenstine, Anne Marie, Ph.D. "Mercapto Group Definition." ThoughtCo, Aug. 25, 2020, thoughtco.com/definition-of-mercapto-group-605335. Helmenstine, Anne Marie, Ph.D. (2020, August 25). Mercapto Group Definition. Retrieved from https://www.thoughtco.com/definition-of-mercapto-group-605335 Helmenstine, Anne Marie, Ph.D. "Mercapto Group Definition." ThoughtCo. https://www.thoughtco.com/definition-of-mercapto-group-605335 (accessed June 10, 2023). copy citation Featured Video