Abstract
UDP-arabinopyranose mutase (UAM) is the eyzyme which catalyses the conversion of UDP-arabinopyranose and UDP-arabinofuranose. UDP-Arabinofuranose is the precursor of arabinofuranose residues. Thus, UAM has an important role on the biosynthesis of cell wall polysaccharide which contains arabinofuranose residues such as arabinan, arabinoxylan, and arabinogalactan. We have cloned UAM gene from Chlamydomonas and prepared the recombinant UAM expressed in E. coli. We analyzed the Km value of recombinant UAM, resulting that the affinity of recombinant UAM for UDP-arabinopyranose dramatically decreased compared to that of rice UAM. In some cases, enzyme activity is regulated by phosphorylation or glycosylation. We found that Chlamydomonas UAM was phosphorylated. We analyze that the effect of phosphorylation of UAM on its enzyme activity.
