Involved in the glycolate utilization. Catalyzes the condensation and subsequent hydrolysis of acetyl-coenzyme A (acetyl-CoA) and glyoxylate to form malate and CoA. acetyl-CoA + glyoxylate + H2O = (S)-malate + CoA + H(+) Mg(2+). Mn(2+) is able to replace Mg(2+). By bromopyruvate, oxalate, and phosphoenolpyruvate. Malate inhibits the activity to 50% at 1 mM concentration. Glycolate inhibits only at fairly high concentrations. Carbohydrate metabolism; glyoxylate cycle; (S)-malate from isocitrate: step 2/2. Homodimer. Belongs to the malate synthase family. GlcB subfamily.