In enzymology, a flavone apiosyltransferase (EC 2.4.2.25) is an enzyme that catalyzes the chemical reaction

UDP-apiose + 5,7,4'-trihydroxyflavone 7-O-beta-D-glucoside ${\displaystyle \rightleftharpoons }$ UDP + 5,7,4'-trihydroxyflavone 7-O-[beta-D-apiosyl-(1->2)-beta-D-glucoside]

Thus, the two substrates of this enzyme are UDP-apiose and 5,7,4'-trihydroxyflavone 7-O-beta-D-glucoside, whereas its 3 products are UDP, 5,7,4'-trihydroxyflavone (apigenin), and [[7-O-[beta-D-apiosyl-(1->2)-beta-D-glucoside]]].

This enzyme belongs to the family of glycosyltransferases, specifically the pentosyltransferases. The systematic name of this enzyme class is UDP-apiose:5,4'-dihydroxyflavone 7-O-beta-D-glucoside 2''-O-beta-D-apiofuranosyltransferase. Other names in common use include uridine diphosphoapiose-flavone apiosyltransferase, and UDP-apiose:7-O-(beta-D-glucosyl)-flavone apiosyltransferase. This enzyme participates in flavonoid biosynthesis.

• Ortmann R, Sutter A, Grisebach H (1972). "Purification and properties of udpapiose: 7-O-( -D-glucosyl)-flavone apiosyltransferase from cell suspension cultures of parsley". Biochim. Biophys. Acta. 289 (2): 293–302. doi:10.1016/0005-2744(72)90080-0. PMID 4650134.