Xylose isomerase, actinobacteria <p> This is an enzyme which as well as interconverting D-xylose and D-xylulose, is also active as a D-glucose isomerase. It is tetrameric and dependent on a divalent cation, either Mg2+, Co2+ or Mn2+, as characterised in Arthrobacter [<cite idref="PUB00020769"/>]. Enzymes in this entry differ substantially from the D-xylose isomerases of <db_xref db="INTERPRO" dbkey="IPR013452"/>.</p>