Sialic acid permease

Three enzyme systems are required for the catabolism of sialic acids 0-acetylesterases, sialidases and lyases. Furthermore, a sialic acid transporter has been described (section 10.5), which carries liberated sialic acids from lysosomes into the cytosol, where they are either degraded by the lyase or recycled after activation with CTP (section 8.3). Sialic acid permeases provide bacteria with sialic acids for nutritional purposes (section 9.4). 

NeuSAc [903]. A A m value of 0.3 mM for NeuSAc was measured for this hypothetical transporter protein. This question has not yet been solved in C. perfringens, although recent experiments have also shown that sialic acid uptake is not due to mere diffusion (C. Traving et al., unpublished). However, in E. coli evidence for a sialic acid permease was obtained, based on molecular biological studies [585,904]. 

Scheme 4.—Induction and Cooperation of the Sialic acid-specific Enzymes Siali-dase, Acylneuraminate Pyruvate-lyase, and Neu5Ac-permease (hypothetical) in Clostridium perfringens. [Key , sialoglycoprotein , free sialic acid f—at>, ...

---