Proteoglycans of Microsomal Fraction of Mouse Mastocytoma

Proteoglycans have been isolated from a microsomal fraction of a mouse mastocytoma by procedures which should minimize alteration of the original protein-polysr, ccharide molecule. The methods used include in vivo labeling of sulfate-containing proteoglycans with³⁵S-sulfate, centrifugation of the tumor homogenate at 105, 000 g, solubilization of the microsomal pellet using sodium dodecyl sulfate, cetylpyridinium fractionation, DEAE-cellulose column chromatography and Geon resin electrophoresis. Two major sulfated proteoglycan fractions were obtained. The analytical data obtained were interpreted to indicate that one of these fractions contained keratan sulfate-like material (KSP), the other a heparin-like polymer (HP). KSP was found to contain sialic acid. The protein content of KSP was considerably higher than that of HP. Results of amino acid analysis indicate that glutamic acid and leucine were predominant in KSP, but serine and glycine in HP. Both KSP and HP were found to be homogeneous when examined using acrylamide gel and cellulose acetate electrophoresis, and HP using Geon resin electrophoresis.