Butyryl-CoA: acetate CoA-transferase (but)

Butyryl-CoA: acetate CoA-transferase (often abbreviated as but) is an enzyme that plays a crucial role in the production of butyrate. The primary function of butyryl-CoA: acetate CoA-transferase is to catalyze the conversion of Butyryl-CoA and acetate into butyrate and acetyl-CoA. This reaction is a key step in the metabolic pathway of butyrate synthesis in many gut bacteria (1, 2, 3).

The butyryl-CoA: acetate CoA-transferase gene is found in various butyrate-producing bacteria within the human colon. These bacteria are primarily Gram-positive Firmicutes, including species related to Eubacterium rectale, Roseburia spp., and Faecalibacterium prausnitzii (3, 4).

The abundance of the butyryl-CoA: acetate CoA-transferase gene can vary with diet and age. For instance, vegetarians tend to have a higher abundance of this gene compared to omnivores, and its abundance decreases with age (1).

References:
(1): Hippe et al. 2011 FEMS Microbiol Lett. 316(2): 130-5
(2): Trachsel et al. 2016 Appl Environ Microbiol. 82(22): 6788-6798
(3): Louis & Flint 2009 FEMS Microbiol Lett. 294(1): 1-8
(4): Louis et al. 2010 Environ Microbiol.12(2): 304-14