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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 3978

T.W. Woodworth, W.E. Keefe, and S.G. Bradley; Characterization of the Proteins of Naegleria fowleri: Relationships between Subunit Size and Charge. J.Protozool. 29(2):246-251, 1982

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Proteins of whole cell extracts of Naegleria fowleri, precipitated with acetone, have been resolved by two-dimensional polyacrylamide gel electrophoresis. Autoradiograms of the [35S]-methionine-labeled polypeptides were scanned and analyzed by a computer-assisted program in order to determine whether there were correlations between selected attributes of proteins (e.g., subunit size and charge). The majority of the polypeptides had molecular sizes within the range of 20-60 kilodaltons. The mean amount of polypeptide was less for those with molecular sizes between 20 and 45 kilodaltons than for those larger than 45 kilodaltons. The mean amount of polypeptide was greater in the isoelectric focusing range of pH 5-6 than in range of pH 6-7. Polypeptides in the size range of 20-40 kilodaltons had a median isoelectric point of 6.1, whereas polypeptides in the size range of 40-80 kilodaltons had a median pI of 5.6. Our data indicated that molecular size and charge were not entirely independent variables, and that the composition of a polypeptide might have an important influence on its steady state level in N. fowleri.