摘要：A hypoalbuminemic substance was purified from mouse Ehrlich ascites carcinoma cells by ammonium sulfate fractionation, adsorption on DEAE-cellulose, gel filtration on Sephadex G-200, treatment with butanol, ultracentrifugation, and gel filtration on Sephadex G-75. Electrophoresis on polyacrylamide gel containing sodium dodecylsulfate gave a single band of protein which corresponded to a molecular weight of 53000. This band was also detected by staining with methylene blue. Significant decreases in serum albumin, serum total protein, and leukocyte count were observed when it was given to mice by intraperitoneal injection. It stimulated the phagocytic activities of the reticuloendothelial system of mice. Of these effects, only the leukocyte-lowering effect disappeared when it was administered to adrenalectomized mice. Hydrocortisone produced a marked decrease in the leukocyte count but no significant change in the serum albumin and total protein when given to normal mice over a period of six days. The vascular permeability-increasing activity concentrated into the fraction unadsorbed on DEAE-cellulose and distinctly separated from the hypoalbuminemic activity. The hypoalbuminemic substance was composed of 28.9% of DNA, 24.9% of hexose, 24.6% of RNA, 14.6% of amino acid residues, and 1% of hexosamine. The lipid content was negligible. The hypoalbuminemic activity decreased considerably at pH 2 or 11 and almost completely disappeared by heating at 60°. This activity was decreased markedly by the partial digestion with Pronase, trypsin, or DNase, whereas the treatment with RNase or the butanol extraction exerted no influence on the activity.
