Identification and Evaluation of CMP-Sialic Acids.

Cytidine 5'-monophosphate-sialic acid (CMP-Sia) is a donor substrate of all sialyltransferases in both prokaryotes and eukaryotes, and biosynthesized by the CMP-Sia synthetase (CSS or CMAS) using Sia and cytidine 5'-triphosphate (CTP) as the substrates. Since CSSs have unique substrate specificity for Sia species depending on organisms, cells, and organs, and developmental stages, various kinds of CMP-Sia exist in nature. This chapter describes how to quantitatively detect CMP-Sia in the CSS reaction mixture as well as in cells and organs.