@article{mbs:/content/journal/micro/10.1099/00221287-139-5-1055, author = "Uttaro, Antonio D. and Ielpi, Luis and Ugalde, Rodolfo A.", title = "Galactose metabolism in Rhizobiaceae: characterization of Agrobacterium tumefaciens exoB mutants", journal= "Microbiology", year = "1993", volume = "139", number = "5", pages = "1055-1062", doi = "https://doi.org/10.1099/00221287-139-5-1055", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-139-5-1055", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = " Agvobacterium tumefaciens exoB mutants (deficient in succinoglycan or EPS I synthesis) were characterized. The defect was determined to be the lack of UDP-glucose 4-epimerase (EC 5.1.3.2) activity. This defect results in absence of UDP-galactose, which is the obligatory intermediate as galactose donor for initiation of the succinoglycan repeating unit on a lipid intermediate. It was determined that A. tumefaciens does not have the Leloir pathway enzyme activities galactokinase (EC 2.7.1.6) and galactose-1-phosphate uridylyltransferase (EC 2.7.7.10). A De Ley-Doudoroff oxidative pathway for galactose metabolism was observed in A. tumefaciens. This pathway is not constitutive and its expression required d-galactose or l-arabinose. However, UDP-glucose 4-epimerase is constitutive and did not require growth on galactose for full expression.", }