Human plasma proapoA-I: isolation and amino-terminal sequence.
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Brewer HB Jr, Fairwell T, Kay L, Meng M, Ronan R, Law S, Light JA
Human plasma proapoA-I: isolation and amino-terminal sequence.
Biochem Biophys Res Commun. 1983 Jun 15;113(2):626-32.
- PubMed ID
- 6409108 [ View in PubMed]
- Abstract
Human apoA-I is synthesized as preproapoA-I, a 267 amino acid precursor apolipoprotein. PreproapoA-I initially undergoes intracellular co-translational proteolytic cleavage into proapoA-I. ProapoA-I is secreted from the cell and was isolated from thoracic duct lymph in the apoA-I1 isoform position. The amino-terminal sequence of proapoA-I isolated from human lymph revealed the presence of 6 additional amino acids, Arg-His-Phe-Trp-Gln-Gln, on the amino-terminal end of apoA-I consistent with the proapoA-I sequence determined by nucleic acid sequence analysis of cloned apoA-I. Our results indicate that proapoA-I is present in human plasma, and undergoes post-translational proteolytic cleavage to mature plasma apoA-I.