Rat alpha 1-microglobulin. Purification from urine and synthesis by hepatocyte monolayers.
Rat alpha 1-microglobulin was isolated from the urine of rats treated with sodium chromate, and was purified by the use of gel chromatography, affinity chromatography on concanavalin-A-Sepharose and ion-exchange chromatography. The protein was heterogeneous in charge, had a tendency to form dimers, and was associated with a brown-coloured chromophore. The size of the protein (25 kDa) was similar to guinea pig alpha 1-microglobulin but smaller than the human protein, when measured with sodium dodecyl sulfate/polyacrylamide gel electrophoresis. Immunological cross-reaction with human and guinea pig alpha 1-microglobulin was demonstrated. The concentration of alpha 1-microglobulin in rat serum was 16.4 mg/l (SD = 8.5 mg/l, n = 13) and rat serum alpha 1-microglobulin was eluted from a gel chromatography column at two different positions corresponding to monomeric alpha 1-microglobulin and IgA. The latter alpha 1-microglobulin activity could be absorbed by anti-IgA serum. Rat alpha 1-microglobulin and albumin were continuously released into the medium of rat hepatocyte monolayers, and alpha 1-microglobulin was isolated from the medium by the use of immunoprecipitation with anti-(alpha 1-microglobulin). Tritiated leucine, added to the medium, was incorporated into the protein, suggesting a de novo synthesis of alpha 1-microglobulin by the hepatocytes. The size of hepatic alpha 1-microglobulin was similar to that of purified urinary rat alpha 1-microglobulin, when determined with sodium dodecyl sulfate/polyacrylamide gel electrophoresis.
Akerström
B
B
Landin
B
B
D000818:Animals; D002478:Cells, Cultured; D055598:Chemical Phenomena; D002621:Chemistry; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000096:biosynthesis* / Q000652:urine; D006168:Guinea Pigs; D007106:Immune Sera; D008930:Mitochondria, Liver / Q000378:metabolism*; D010172:Palmitoylcarnitine / Q000096:biosynthesis; D010316:Particle Size; D051381:Rats; D012967:Sodium Dodecyl Sulfate; D000511:alpha-Macroglobulins / Q000096:biosynthesis* / Q000276:immunology / Q000652:urine
D006023:Glycoproteins; D007106:Immune Sera; D000511:alpha-Macroglobulins; D010172:Palmitoylcarnitine; D012967:Sodium Dodecyl Sulfate