In enzymology, a N-acylneuraminate cytidylyltransferase (EC 2.7.7.43) is an enzyme that catalyzes the chemical reaction:CTP + N-acylneuraminate diphosphate + CMP-N-acylneuraminate. Thus, the two substrates of this enzyme are CTP and N-acylneuraminate, whereas its two products are diphosphate and CMP-N-acylneuraminate. This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing nucleotide groups (nucleotidyltransferases). This enzyme participates in aminosugars metabolism.http://www.creative-enzymes.com/product/CMPSialic-Acid-Synthetase-From-Neisseria-Meningitidis-Group-B-Recombinant_1569.html