Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Familial hypoalphalipoproteinemia (hypoalpha), characterized by a decreased high density lipoprotein level, is associated with an increased incidence of premature cardiovascular disease. Restriction fragment length polymorphism analysis of genomic DNA has detected a polymorphism for the PstI restriction endonuclease near the apoA-I gene, with either a 2.2 or a 3.3 kb fragment. The latter has been previously found to occur with significantly higher frequency in probands of families with familial hypoalpha. ApoA-I was isolated from three unrelated subjects with familial hypoalpha and the 3.3 kb PstI polymorphism of the apoA-I gene, and from normal control subjects. The apoA-I from the hypoalpha subjects was structurally normal as determined by amino acid analysis and by two-dimensional gel electrophoresis. When normal apoA-I and hypoalpha apoA-I were simultaneously injected into either normal controls or hypoalpha subjects, both forms of apoA-I were catabolized at the same rate in the same subject, indicating that the hypoalpha apoA-I is also metabolically normal. Analysis of the kinetics of metabolism of apoA-I in the hypoalpha subjects, compared to the normal controls, revealed that the reduced plasma levels of apoA-I were due to an increased apoA-I fractional catabolic rate, and that the synthetic rate was normal. Based on these results, we conclude that the apoA-I gene in these hypoalpha subjects is normal, and the PstI polymorphism near the apoA-I gene, which is associated with familial hypoalpha, is likely to be a marker for a mutant gene closely linked to, but not in, the apoA-I gene.
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PMID:Apolipoprotein A-I metabolism in subjects with a PstI restriction fragment length polymorphism of the apoA-I gene and familial hypoalphalipoproteinemia. 198 93

Coronary artery disease (CAD) is the leading cause of morbidity and mortality in most industrialized countries, accounting for one out of every two deaths in the United States. Disorders of the lipid transport system resulting from complex interactions among nutritional, environmental and genetic factors, play a very important role in the development of this disease. It has been proposed that low density lipoproteins (LDL) cause cholesterol deposition in the arterial wall, whereas high density lipoproteins (HDL) promote efflux of cholesterol from this site. Thus, low levels of HDL and/or high levels of LDL, have been associated with increased risk of CAD. Apolipoprotein A-I (Apo A-I) is the major protein component of HDL, and it has been proposed that the levels of this protein are a better predictor of risk of CAD than the level of cholesterol in HDL. The human Apo A-I gene has been characterized, and it has been found to be adjacent to the genes for apolipoproteins C-lll and A-lV on the long arm of chromosome 11. The cloning of these genes provides the appropriate tools to apply molecular genetic techniques to find differences between individuals at the gene level (restriction fragment length polymorphisms, RFLP) and to identify specific alleles at this particular gene locus which may be associated with a clinical phenotype, more specifically, premature CAD and familial hypoalphalipoproteinemia. In a preliminary study we have identified a Pst I restriction-endonuclease site flanking the human apolipoprotein A-I gene at its 3' end that is polymorphic.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Coronary artery disease, lipid disorders and genetic polymorphisms. 289 7

We have isolated full-length cDNA clones for apolipoprotein AI from a human fetal liver cDNA library made in the vector lambda gt10. One such clone, pBL13AI, was 965 nucleotides long and contained the entire preproapolipoprotein AI sequence, in addition to 86 nucleotides of 5' untranslated region and 75 nucleotides of the 3' untranslated region. The complete structure of this clone is presented. Furthermore, we have obtained a 20-kb genomic fragment from a human genomic library, encompassing the entire apo AI gene. Sequence analysis of the gene shows that the coding region is interrupted by three introns of 197, 187, and 588 bp, respectively. Digestion of the DNA of various individuals with the endonuclease Msp I revealed a new restriction site polymorphism in the apo AI gene.
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PMID:Isolation and DNA sequence of full-length cDNA and of the entire gene for human apolipoprotein AI--discovery of a new genetic polymorphism in the apo AI gene. 620 99

Apolipoprotein A-I (apoA-I) serves critical functions in plasma lipoprotein metabolism as a structural component of high density lipoprotein, activator of lecithin:cholesterol acyltransferase, and acceptor of cellular cholesterol as part of the reverse cholesterol transport pathway. In an effort to facilitate structure:function studies of human apoA-I, we have optimized a plasmid vector for production of recombinant wild type (WT) and mutant apoA-I in bacteria. To facilitate mutagenesis studies, subcloning, and DNA manipulation, numerous silent mutations have been introduced into the apoA-I cDNA, generating 13 unique restriction endonuclease sites. The coding sequence for human apoA-I has been modified by the introduction of additional silent mutations that eliminate 18 separate codons that employ tRNAs that are of low or moderate abundance in Escherichia coli. Yields of recombinant apoA-I achieved using the optimized cDNA were 100+/-20 mg/L bacterial culture, more than fivefold greater than yields routinely obtained with the original cDNA. Site-directed mutagenesis of the apoA-I cDNA was performed to generate a Glu2Asp mutation in the N-terminal sequence of apoA-I. This modification, which creates an acid labile Asp-Pro peptide bond between amino acids 2 and 3, permits specific chemical cleavage of an N-terminal His-Tag fusion peptide used for rapid protein purification. The product protein's primary structure is identical to WT apoA-I in all other respects. Together, these changes in apoA-I cDNA and bacterial expression protocol significantly improve the yield of apoA-I protein without compromising the relative ease of purification.
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PMID:Optimized bacterial expression of human apolipoprotein A-I. 1250 90