Acetyl-CoA carboxylase, carboxyltransferase domain (ACC-CT) (ACC-CT)

Acetyl-CoA carboxylase (ACC) is a vital biotin-dependent enzyme that catalyzes the conversion of acetyl-CoA to malonyl-CoA, the first and rate-limiting step in fatty acid biosynthesis (NIH, 2025; MDPI, 2022). In plants, ACC exists in two main forms: a heteromeric (multisubunit) form found in the plastids of most dicots and a homomeric (multidomain) form found in the cytosol of all plants and the plastids of grasses (Gramineae) (Frontiers, 2023). The carboxyltransferase (CT) domain is the specific catalytic site where the activated carboxyl group is transferred from carboxybiotin to acetyl-CoA (Columbia.edu, 2022). This domain is the primary target for three major classes of grass-selective herbicides: aryloxyphenoxypropionates (FOPs), cyclohexanediones (DIMs), and phenylpyrazolines (DENs) (PNAS, 2007). These herbicides selectively inhibit the homomeric plastid ACCase in grasses, making them effective for controlling grass weeds in broadleaf crops (UWA, 2022). Resistance to these herbicides is a significant agricultural challenge, often arising from single-site mutations within the CT domain that alter the herbicide-binding pocket (MDPI, 2024). Additionally, the plant CT domain serves as a structural model for developing human ACC inhibitors to treat metabolic diseases such as obesity and type 2 diabetes (NIH, 2022; RCSB, 2003).

Other names

ACCaseAcetyl-CoA carboxylase carboxyltransferase subunitCT domainPlastid ACCaseHomomeric acetyl-CoA carboxylase

Inhibition of the carboxyltransferase (CT) activity of acetyl-CoA carboxylase, which prevents the transfer of the carboxyl group from carboxybiotin to acetyl-CoA, thereby blocking the production of malonyl-CoA and halting de novo fatty acid biosynthesis (NIH, 2025; Columbia.edu, 2022).