Galacturonate

Another microbial polysaccharide-based emulsifier is Hposan, produced by the yeast Candida lipolytica when grown on hydrocarbons (223). Liposan is apparentiy induced by certain water-immiscible hydrocarbons. It is composed of approximately 83% polysaccharide and 17% protein (224). The polysaccharide portion consists of D-glucose, D-galactose, 2-amino-2-deoxy-D-galactose, and D-galacturonic acid. The presence of fatty acyl groups has not been demonstrated the protein portion may confer some hydrophobic properties on the complex. 

Principal polysaccharide constituent listed. Sugars are D- unless otherwise noted. Ara = arabinose Gal = galactose GalA = galacturonic acid ... 

Bromophenol blue (3.0...4.6) aliphatic carboxylic acids [225 — 228] malonic and lactic acids [229] palmitic and lactic acids [230] malonic, glycolic, malic, citric, tartaric, ketoglutaric, galacturonic and oxalic acids [196] dicarboxylic acids, succinic acid [231] indoleacetic acid, trichloroacetic acid [232] palmitic acid, palmityl- and stearyllactic acid [223] benzoic, sorbic and salicylic acid [234] metabolites of ascorbic acid [235] chloropropionic acid [236] oligogalacturonic acids [237] amino acids, hydrocarbons, mono-, di- and triglycerides [238] xylobiose, xylose, glucose and derivatives [239] sugar alcohols [91] toxaphene [240]... 

Synthesis of Uronic Acids. Part II. 2 3 4-Trimethyl Derivatives of Mannuronic, Glucuronic, and Galacturonic Acids, F. Smith, M. Stacey, and P. I. Wilson, J. Chem. Soc., (1944) 131-134. 

Deoxy-sugars. Part XXI. Synthesis of Some Derivatives of 2-Deoxy-D-galacturonic Acid, W. G. Overend, F. Shafizadeh, and M. Stacey, J. Chem. Soc., (1951) 1487-1489. 

Pectin belongs to a family of plant polysaccharides in which the polymer backbone consists of (1— 4)-linked a-D-galacturonic acid repeating-units. Often, (1— 2)-linked a-L-rhamnose residues interrupt the regular polygalacturonate sequence. The high viscosity and gelling properties of pectins are exploited by the food and pharmaceutical industries. X-Ray studies on sodium pectate, calcium pectate, pectic acid, and pectinic acid (methyl ester of pectic acid) have disclosed their structural details. 

The other polymer denominated PMII [18,72,73], is a pectic type polymer with mainly a galacturonic acid backbone. The structure of PMII was... 

The stems of the tree were foimd to contain polysaccharides consisting of arabinose, galactose and galacturonic acid and only minor amoimts of rham-nose. Structural studies indicate that the polymeric material consists of 1,4-linked galacturonic acid residues, terminal, 1,4-, 1,6- and 1,3,6 galactose units and terminal and 1,5-linked arabinofuranose residues. Further studies must be performed on this in order to determine what type of pectin it can be classified as. The Hnkage data indicate that both AG-I and AG-II are present. This polymer was shown to activate polyclonal B-cells [78]. 

Figure 2 Structures of D-glucuronic (GlucA 1), o-galacturonic (GalA 2), and o-gluconic (GluA 3) acids.

---