Immunoprecipitation is inappropriate for the isolation of radiochemically pure albumin from tissues
✍ Scribed by Jörg Urban; Peter Zimber; Gerhard Schreiber
- Publisher
- Elsevier Science
- Year
- 1974
- Tongue
- English
- Weight
- 925 KB
- Volume
- 58
- Category
- Article
- ISSN
- 0003-2697
No coin nor oath required. For personal study only.
✦ Synopsis
Rats were given intravenous injections of r.-[l-'4Clleucine.
Twelve minutes after injection, testes, kidneys, livers, and hepatomas were excised rapidly from one group of animals bearing Morris hepatoma 5123tc. From a second group of rats, the blood was removed 90 min after injection. Tissue extracts and serum were divided into three portions each, and albumin was isolated from each of the three portions by one of three different methods.
The three different isolation procedures were the following: (A) pretreatment of the tissue extracts and serum with bovine serum albumin and its specific antiserum and subsequent immunoprecipitation of the rat, serum albumin, (B) direct immunoprecipitation followed by dissolving the precipitated rat serum albumin in acid/ethanol, precipitation with ether, and ion-exchange chromatography of the redissolved albumin on CM-cellulose, and (C) a modificat,ion of a procedure published previously including fractionation with trichloroacetic acid, ethanol, ether, and ammonium sulfate, chromatography on Sephadex G-100 and DEAE-cellulose, and preparative disc electrophoresis in polyacrylamide gel at pH 10.3 and pH 2.7.
With method (A), radiochemically pure albumin can be obtained only from serum. Even though testis and kidney do not synthesize albumin, albumin preparations isolated by this procedure from these organs contain significant amounts of radioactivity. Specific radioactivities measured in albumin prepared by method (A) from the four tissues examined are 5-19 times larger than those in preparations isolated by method (C). Thus, method (A) is inappropriate for the isolation of radiochemically pure albumin from the tissues studied.
Procedure (B) is sufficient to obtain radiochemically pure albumin from the serum as well as from the other tissues examined except liver. With liver, this method yields an albumin preparation containing 53% more radioactivity than does albumin isolated with method (C). Method (C) is the only procedure yielding radiochemically pure albumin from all sources, including liver. In liver and hepatoma, t.he properties of the radioactive impurities are very similar to the properties of albumin