Isoelectric focusing of mycoplasma proteins.

Polyacrylamide gel isoelectric focusing (PAGIF) in thin layer was used to resolve proteins of Mycoplasma spp., Acholeplasma spp., and eight strains of Ureaplasma urealyticum (T-strain). A mixture of urea, Triton X-100, and dithioerythritol was used to solubilize sonically disrupted cells. PAGIF was performed in the range of pH 3 to 10. Protein patterns were carefully compared, demonstrating resolved and distinguishable species-specific protein bands. The eight serotypes of U. urealyticum (T-strain) gave identical protein patterns in the pH 3 to 10 range. The characteristic "fingerprints" of a species appeared to correlate with the biochemical nature and not the habitat in each case. Arginine-hydrolyzing species seemed to show more diverse focusing than those that ferment glucose, or prefer an acid environment. Characterization and identification of highly resolved species-specific proteins, ease of performance, and reproducibility of this method suggest that PAGIF might be employed as a taxonomic aid.