-!- The enzyme is involved in biosynthesis of 2-O-(alpha-D- glucopyranosyl)-D-glycerate via the two-step pathway in which glucosyl-3-phosphoglycerate synthase catalyzes the conversion of GDP- glucose and 3-phospho-D-glycerate into 2-O-(alpha-D-glucopyranosyl)- 3-phospho-D-glycerate, which is then converted to 2-O-(alpha-D- glucopyranosyl)-D-glycerate by EC 3.1.3.85. -!- The activity is dependent on divalent cations (Mn(2+), Co(2+), or Mg(2+)). -!- The enzyme from Persephonella marina shows moderate flexibility on the sugar donor concerning the nucleotide moiety (UDP-glucose, ADP- glucose, GDP-glucose) but is strictly specific for glucose. -!- The enzyme is also strictly specific for 3-phospho-D-glycerate as acceptor. -!- The enzyme from Methanococcoides burtonii is strictly specific for GDP-glucose and 3-phospho-D-glycerate. -!- This enzyme catalyzes the first glucosylation step in methylglucose lipopolysaccharide biosynthesis in mycobacteria.