Hemocyanins in Spiders, IX. Homogeneity, Subunit Composition and the Basic Oligomeric Structure ofEurypelma californicumHemocyanin

Abstract

37S hemocyanin isolated from the tarantula E. californicum was subjected to a variety of fractionation procedures: electrophoresis in polyacrylamide gels, isoelectrofocusing and ion exchange chromatography. Single fractions were dissociated at alkaline pH and/or by sodium dodecyl sulfate and the resulting subunits separated by polyacrylamide gel electrophoresis in gradient slab gels followed, in many cases, by quantitative estimation of the subunit bands. Crossed immunoelectrophoresis was employed to analyze the subunit composition. Separation of the native hemocyanin into fractions with different subunit composition was not observed. Hemocyanin samples taken from individual spiders showed a strikingly uniform composition. Eurypelma hemocyanin is homogeneous for all practical means. Seven different polypeptide chains described previously for Eurypelma hemocyanin probably take part in the formation of the 24 subunits, 37S oligomeric molecule.