J. R. Edwards, J. A. Hayashi
Aug 1, 1965
Citations
3
Influential Citations
154
Citations
Quality indicators
Journal
Archives of biochemistry and biophysics
Abstract
Abstract The rhamnolipid produced in culture filtrates of Pseudomonas aeruginosa grown on glycerol has been shown to have the structure 2-O-α- l -rhamnopyranosyl-α- l rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoate. Periodate oxidation of the rhamnolipid resulted in the consumption of 2.8 moles of periodate per mole of substrate in 120 hours. Sodium borohydride reduction, acid hydrolysis, and paper chromatography of the products of the oxidation over the 120-hour period showed the initial (24 hours) appearance of both propylene glycol and butanetriol with complete loss of rhamnose. At the end of the oxidation period, only propylene glycol remained, an indication that the first 2 moles of periodate each attacked a different rhamnosyl moiety with slow oxidation of the terminal rhamnose by the third mole of periodate. Methylation of the rhamnolipid, subsequent hydrolysis, and identification of the methylrhamnoses by paper chromatography, paper electrophoresis, and gas chromatography showed the presence of 2,3,4-tri- O -methylrhamnopyranoside and 3,4-di- O -methylrhamnopyranoside. The constituent methylrhamnosides were further identified by forming the phenylhydrazide of the bromine-oxidized 2,3,4-tri- O -methylrhamnopyranoside and by reducing the dimethyl compound to the 3,4-di- O -methylrhamnitol and identifying the formaldehyde formed after periodate oxidation. The alpha configuration has been assigned to the rhamnosyl residues of the rhamnolipid on the basis of a high negative optical rotation, increase in rotation during acid hydrolysis, and infrared spectral similarities with methyl α- l -rhamnopyranoside.