Precursor of rat liver alpha 2u-globulin: partial amino acid sequence determination of its signal peptide.
The biosynthesis of alpha 2 u-globulin, the major protein in rat urine, was studied in a cell-free system programmed with messenger RNA isolated from rat liver. Analysis of the primary translation product by SDS-polyacrylamide gel electrophoresis showed a molecular weight of approximatley 22,000 daltons as compared to 20,000 daltons for the mature form. When translation was carried out in the presence of dog pancreas microsomes, alpha 2u-globulin was cotranslationally processed and sequestered in the microsomal lumen. Automated sequencing to mature alpha 2u-globulin and the labeled precursor disclosed the presence of 19 additional amino acids at the amino-terminal end of the primary translation product of the urinary alpha 2u-globulin. The partial amino acid sequence of this extension was determined.
D000510:Alpha-Globulins / Q000096:biosynthesis* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D002474:Cell-Free System; D004285:Dogs; D004721:Endoplasmic Reticulum / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000378:metabolism; D051381:Rats
D000510:Alpha-Globulins; D011498:Protein Precursors; C013803:alpha 2u globulin