Dr. Stephen Seah

I have always been fascinated by how proteins, made up of simple building blocks of 20 amino acids, could serve the diverse functions required in living systems. My lab is studying microbial enzymes related by convergent and divergent evolution to decipher structure-function relationships in proteins. Target enzymes being investigated include those important for environmental pollutant degradation and those that are medically relevant.

• B.Sc. National University of Singapore
• M.Sc. National University of Singapore
• Ph.D. University of Sheffield, UK

We employ a variety of interdisciplinary techniques in our research, including molecular cloning, gene knockout, site-specific mutagenesis, protein purification, various spectroscopic methods and structural biology. Current research projects include:

1. Steroid degradation in Mycobacterium tuberculosis and other bacteria.
Although most bacteria do not synthesize steroids, many can chemically modify them and even use steroids as carbon and energy sources for growth. This microbial capacity for steroid transformation is relevant to the pathogenesis of Mycobacterium tuberculosis, plays an important role in gut health, and can also be leveraged for the biotechnological production of steroid pharmaceuticals that are used as antimicrobial, anti-cancer and anti-inflammatory drugs.

2. Study of microbial enzymes involved in degradation of aromatic pollutants and mycotoxins that contaminate the environment and food.

Recent Selected Publications

1. Rolfe N, Schroeter KL, Forrester TJ, Kimber MS, and Seah SYK. (2025) Sal is a proteobacterial bile acid aldolase that repurposes key thiolase catalytic residues for retroaldol cleavage of C₅ steroid side chains. J Biol Chem. 301:110439.

2. Abraham, N., Chan, E., Li, XZ, Zhu H, Mats L, Zhou T, and Seah SYK. (2025) Patulin Detoxification by Evolutionarily Divergent Reductases of Gluconobacter oxydans ATCC 621. J Agric Food Chem. 73:6842-685

3. Schroeter KL, Rolfe N, Forrester TJB, Kimber MS, and Seah SYK (2024) Shy is a proteobacterial steroid hydratase which catalyzes steroid side chain degradation without requiring a catalytically inert partner domain. J Biol Chem. 300:107509.

4. Schroeter, K.L., Abraham, N., Rolfe, N., Barnshaw, R., Diamond, J. and Seah, S.Y.K. (2022) Bacterial hydratases involved in steroid side-chain degradation have distinct substrate specificities. J. Bacteriol. 204:e0023622

• Avalene Kong (PhD)
• Parker Sear (MSc)