Catalyzes the cleavage of N-acetylneuraminic acid (sialic acid) to form pyruvate and N-acetylmannosamine via a Schiff base intermediate . It prevents sialic acids from being recycled and returning to the cell surface . Involved in the N-glycolylneuraminic acid (Neu5Gc) degradation pathway (, ). Although human is not able to catalyze formation of Neu5Gc due to the inactive CMAHP enzyme, Neu5Gc is present in food and must be degraded (Probable).
Subcellular locations: Cytoplasm
Isoform 2 is expressed in placenta, liver, kidney, pancreas, spleen, thymus, ovary, small intestine and peripheral blood leukocyte.