Human apolipoprotein E (apoE) was produced in Escherichia coli by transforming cells with an expression vector containing a reconstructed apoE cDNA, a X PL promoter regulated by the thermolabile cI repressor, and a ribosomal binding site derived from the X cIT or the E. coli f3-lactamase gene. Transformed cells induced at 420C for short periods of time (<20 min) produced apoE, which accumulated in the cells at levels of m1% of the total soluble cellular protein.Longer induction periods resulted in cell lysis and the proteolytic destruction of apoE. The bacterially produced apoE was purified by heparin-Sepharose affinity chromatography,

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Human Mn superoxide dismutase (MnSOD) encoded by chromosome 6 is a mitochondrial matrix enzyme positioned to scavenge oxygen radicals produced by the extensive oxidation-reduction and electron transport reactions undergoing in that organelle. cDNA clones containing the entire coding region for human MnSOD were isolated from a T-lymphocyte cDNA library in A gt1O. The cDNA contains a 666 bp coding region followed by a 3' untranslated region which lacks the AATAAA polyadenylation signal. The predicted amino acid sequence is in accordance with the published amino acid sequence of human liver MnSOD (1) with the following exceptions: Glu instead of Gln at positions 42, 88 and 109 and an additional Gly-Trp after amino acids 123. The deduced protein sequence extends 24 amino acids upstream from the N-terminal Lys of human MnSOD, suggesting a pre-peptide. Hence human MnSOD is composed of 222 amino acids, 24 of which are removed during processing and maturation of the enzyme.

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