Apolipoprotein E5 and E7 in apparently healthy Japanese males: Frequencies and relation to plasma lipid levels

Abstract

SummaryIn order to determine the frequencies of apolipoproteins (apo) E5 and E7 and their relation to plasma lipid levels, apo E phenotypes were determined in 608 healthy Japanese male adults by two-dimensional gel electrophoresis. Apo E5 and E7 were observed in 2.8~ of the subjects, in addition to the three common apo E isoforms, E2, E3, and E4. Apo E5 was divided into two subtypes based on the migration rate on SDS/PAGE, E5f is the type with faster migration and E5s slower migration. The gene frequencies were: the ~3 allele, 0.841; the ~4 allele, 0.095; the ~2 allele, 0.049; the ~7 allele, 0.009; the ~5 allele encoding apo E5f (the r allele), 0.004; and the e5 allele encoding apo E5s (the ~5s allele), 0.001. The five individuals with apo E5f and the eleven with apo E7 were heterozygotes and normocholesterolemic. Also plasma apo B and apo E levels were not increased in any subjects with apo E5f or apo E7. The data suggests that apo E5f and E7 are not rare in the Japanese population but that neither apo E5f nor E7 are associated with hypercholesterolemia in most of the heterozygotes.

A novel apolipoprotein E5 variant with a 24-bp insertion causing hyperlipidemia

“…In addition, the gene frequency of apo ε5 was about 0.005, which was the highest next to those of the common apo E alleles (ε3, ε4, and ε2) and apo ε7. We have already reported apo E5s detected by two-dimensional electrophoresis (2-DE) (Yamanouchi et al 1994). In this study, we present another novel apo E5 variant, E5ss.…”

“…Plasma apo E phenotypes were determined by 2-DE according to the method of O'Farrell (1975) with slight modifications to detect apo E variants with the basic PI (Yamanouchi et al 1994). The apo E spots on the slab gels were confirmed by immunoblotting with an anti-human apo E antibody (Cappel Laboratories Inc., Malvern, PA, USA).…”

“…The serum levels of TC, TG, high-density lipoprotein cholesterol (HDL-C), apo B, apo E, apo AI, apo AII, apo CII, and apo CIII were measured according to the method of Yamanouchi et al (1994).…”

“…It migrates faster than apo E3 during sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) (Yamamura et al 1984;Tajima et al 1988;Maeda et al 1989). The receptor binding activity of apo E5 [APOE,E3K] is about twice that of apo E3 (Dong et al 1990;Wardell et al 1991 (Mailly et al 1991;Ruzicka et al 1993;Feussner et al 1996;Yamanouchi et al 1994) . In addition, the gene frequency of apo ε5 was about 0.005, which was the highest next to those of the common apo E alleles (ε3, ε4, and ε2) and apo ε7.…”

Role of apolipoprotein E polymorphism as a prognostic marker in traumatic brain injury and neurodegenerative disease: a critical review

“…Although the existence of E5 (further divided into E5f and E5s based on fast and slow migration in SDS-PAGE) and E7 isoforms is known, 81 their present roles are not well defined. The polymorphism affects 2 key properties of Apo-E: domain interaction and protein stability or molten globule (stable folded intermediate of unstable unfolded protein) formation.…”