biostudies-literatureRapin MNEngineering and Physical Sciences Research Councile14079https://www.ebi.ac.uk/biostudies/studies/S-EPMC10953000biostudies-literatureUnknown175(6)All land-plant cell walls possess hemicelluloses, cellulose and anionic pectin. The walls of their cousins, the charophytic algae, exhibit some similarities to land plants' but also major differences. Charophyte 'pectins' are extractable by conventional land-plant methods, although they differ significantly in composition. Here, we explore 'pectins' of an early-diverging charophyte, Chlorokybus atmophyticus, characterising the anionic polysaccharides that may be comparable to 'pectins' in other streptophytes. Chlorokybus 'pectin' was anionic and upon acid hydrolysis gave GlcA, GalA and sulphate, plus neutral sugars (Ara≈Glc>Gal>Xyl); Rha was undetectable. Most Gal was the l-enantiomer. A relatively acid-resistant disaccharide was characterised as β-d-GlcA-(1→4)-l-Gal. Two Chlorokybus 'pectPhysiologia plantarumSame but different - pseudo-pectin in the charophytic alga Chlorokybus atmophyticus.PMC10953000EP/S023631/1Bothwell JHFry SCMurray LSadler IHRapin MNfalseSame but different - pseudo-pectin in the charophytic alga Chlorokybus atmophyticus.All land-plant cell walls possess hemicelluloses, cellulose and anionic pectin. The walls of their cousins, the charophytic algae, exhibit some similarities to land plants' but also major differences. Charophyte 'pectins' are extractable by conventional land-plant methods, although they differ significantly in composition. Here, we explore 'pectins' of an early-diverging charophyte, Chlorokybus atmophyticus, characterising the anionic polysaccharides that may be comparable to 'pectins' in other streptophytes. Chlorokybus 'pectin' was anionic and upon acid hydrolysis gave GlcA, GalA and sulphate, plus neutral sugars (Ara≈Glc>Gal>Xyl); Rha was undetectable. Most Gal was the l-enantiomer. A relatively acid-resistant disaccharide was characterised as β-d-GlcA-(1→4)-l-Gal. Two Chlorokybus 'pect2023-01-01T00:00:00Z2023 Nov-Dec2026-07-14T20:34:03.161Z2025-04-06T00:24:10.581ZS-EPMC109530003814822910.1111/ppl.14079