Apiose is a branched-chain sugar found as residues in galacturonans-type pectins; that occurs in parsley and many other plants. Apiose is a component of cell wall polysaccharides.
Apiose 1-reductase uses <small>D</small>-apiitol and NAD<sup>+</sup> to produce apiitol-apiose, NADH, and H<sup>+</sup>.
Flavone apiosyltransferase uses UDP-apiose and 5,7,4'-trihydroxyflavone 7-O-ò-<small>D</small>-glucoside to produce UDP, 5,7,4'-trihydroxyflavone (apigenin), and 7-O-ò-<small>D</small>-apiosyl-(1->2)-ò-apiitol-glucoside.