In vitro biosynthesis of 1,4-ß-galactan attached to a pectin-xyloglucan complex in pea

Abstract

Particulate enzyme preparations were prepared from etiolated pea (Pisum sativum L.) epicotyls and used to assay for 1,4-β-galactan synthase using UDP-[U-14C]galactose. Optimum conditions for 1,4-β-galactan synthesis were determined. The enzyme products were characterized by selective enzymic degradation, gel permeation chromatography and anion-exchange chromatography. Evidence was obtained for the formation of 1,4-β-galactan chain attached to a pectic backbone containing both polygalacturonic acid and rhamnogalacturonan I. The results also indicated that part or all of this nascent pectin was present as a complex with xyloglucan.