Conversion of rat pre-proalbumin to proalbumin in vitro by ascites membranes. Demonstration by NH2-TERMINAL SEQUENCE ANALYSIS.
Rat liver poly(A)-containing RNA was translated in an ascites cell-free system. Labeled protein precipitable by antibody directed against rat serum albumin was identified as pre-proalbumin based on its size and partial NH2-terminal sequence. However, when an ascites membrane fraction was added to the translation reaction, the albumin antibody-precipitable material was smaller than pre-proalbumin. Partial NH2-terminal sequence analysis of this protein revealed that it was proalbumin. Conversion of pre-proalbumin to proalbumin by the ascites membrane fraction was complete and precise--i.e. no serum albumin was observed. Reconstitution in vitro of the processing of pre-proalbumin to its stable intracellular form, proalbumin, provides a method for studying the initial proteloytic event involved in secretion of rat serum albumin.
D000595:Amino Acid Sequence; D000818:Animals; D001120:Arginine / Q000378:metabolism; D001201:Ascites / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002474:Cell-Free System; D007930:Leucine / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008715:Methionine / Q000378:metabolism; D011061:Poly A / Q000378:metabolism; D011228:Prealbumin / Q000096:biosynthesis*; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000378:metabolism*; D051381:Rats; D012709:Serum Albumin / Q000096:biosynthesis*
D011228:Prealbumin; D011498:Protein Precursors; D012709:Serum Albumin; D011061:Poly A; D001120:Arginine; D008715:Methionine; D007930:Leucine