**4. Conclusion**

CPSA molecue has a very common modification on its surface. Pyruvylation of sugars is fairly common yet an extensive search of the literature reveals little on successful isolations of an enzyme responsible for this sugar modification. However, very recently a family of genes has been identified that appear to be involved in pyruvate transfer reactions in prokaryotes. A publication in 2013 showed successful purification of pyruvyltransferase Pvg1p from the eukaryote *Schizosaccharomyces pombe*. This group demonstrated the activity of Pvg1p on beta-nitrophenyl galactose, a substrate analogue of galactose [54]. Apart from this eukaryotic pyruvyltransferase Pvg1p and the prokaryotic pyruvyltransferase PssM from *R. leguminosarum*, no other pyruvyltransferases have been characterized [55]. More studies are needed in uncovering this family of enzymes, and also a path needs to be elucidated towards the polymerization of CPSA, to reap its full therapeutic benefits.
