Polygalacturonate 4 alpha galacturonosyltransferase

In enzymology, a polygalacturonate 4-alpha-galacturonosyltransferase (EC 2.4.1.43) is an enzyme that catalyzes the chemical reaction

UDP-D-galacturonate + (1,4-alpha-D-galacturonosyl)n ⇌ UDP + (1,4-alpha-D-galacturonosyl)n⁺1

Thus, the two substrates of this enzyme are UDP-D-galacturonate and (1,4-alpha-D-galacturonosyl)n, whereas its two products are UDP and (1,4-alpha-D-galacturonosyl)n+1.

This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is UDP-D-galacturonate:1,4-alpha-poly-D-galacturonate 4-alpha-D-galacturonosyltransferase. Other names in common use include UDP galacturonate-polygalacturonate alpha-galacturonosyltransferase, uridine diphosphogalacturonate-polygalacturonate, and alpha-galacturonosyltransferase. This enzyme participates in starch and sucrose metabolism and nucleotide sugars metabolism.