Fig. 5

Confirming the biosynthesis of acetyl-CoA from formaldehyde by the SACA pathway in vitro. a The synthesis of glycolaldehyde from formaldehyde by GALS. Reactions were executed under different formaldehyde concentrations with 2 mg mL⁻¹ purified GALS at 37 °C for 2 h. b The inhibition of ACPS by formaldehyde. The yields of acetic acid were measured at different time points with reaction buffer, 2 mg mL⁻¹ ACPS, 0.75 g L⁻¹ glycolaldehyde and the gradient of formaldehyde from 0 to 2 g L⁻¹ which was represented by different color lines. c Yield of acetic acid from different formaldehyde concentrations. Reactions were carried out at 37 °C overnight with reaction buffer, 2 mg mL⁻¹ GALS, 2 mg mL⁻¹ ACPS and the gradient of formaldehyde from 0.5 to 2 g L⁻¹. d Yield of acetic acid or acetyl-CoA from 1 g L⁻¹ formaldehyde. The yields of acetic acid or acetyl-CoA were measured at different time points. The blue line represents the reaction system to produce acetyl-CoA (with 20 mM CoA feeding and containing 2 mg mL⁻¹ of the purified GALS, ACPS, and PTA, respectively); the orange line represents the reaction system to produce acetic acid (containing 2 mg mL⁻¹ GALS and ACPS and without CoA feeding). Samples in all assays were analyzed by HPLC. Error bars represent s.d. (standard deviation), n = 3. Source data are provided as a Source Data file.