Involved in pyrimidine catabolism. Catalyzes the deamination of 3-aminoacrylate to malonic semialdehyde, a reaction that can also occur spontaneously. RutC may facilitate the reaction and modulate the metabolic fitness, rather than catalyzing essential functions. (Z)-3-aminoacrylate + H(+) + H2O = 3-oxopropanoate + NH4(+) Belongs to the RutC family.