title: An exo-D-galacturonanase of Butyrivibrio fibrisolvens from the bovine rumen.
abstract: An intracellular pectinolytic enzyme was isolated from a cell extract of Butyrivibrio fibrisolvens and purified. The optimum pH for enzyme activity was 5.6. The enzyme preferentially degraded de-esterified substrates by hydrolysis of monosaccharide units from the non-reducing end; the only product of degradation was D-galacturonic acid. Values of Km and Vmax for oligo- and polygalacturonates indicated that the best substrate was digalacturonic acid; oligogalacturonates containing either a saturated or a delta 4,5-unsaturated non-reducing end were both degraded. The enzyme was classified as an exo-D-galacturonanase [poly(1,4-alpha-D-galacturonide) galacturonohydrolase (EC 3.2.1.67)].
mesh_terms: D000818:Animals; D002417:Cattle; D002845:Chromatography; D005051:Eubacterium / Q000201:enzymology*; D006026:Glycoside Hydrolases / Q000302:isolation & purification*; D006868:Hydrolysis; D010368:Pectins / Q000378:metabolism; D012417:Rumen / Q000382:microbiology*
chemical_list: D010368:Pectins; D006026:Glycoside Hydrolases; C020136:exopolygalacturonase; C003181:polygalacturonic acid