Anti-Human PCSK2 (a.a. 201-300) Polyclonal antibody

Proinsulin is converted to insulin by the concerted action of two sequence-specific subtilisin-like proteases termed prohormone convertase 2 (PC2) and prohormone convertase 3. PC2 is a type II proinsulin-processing enzyme, and it cleaves the proinsulin molecule on the COOH-terminal side of dibasic peptide, Lys(64)-Arg(65), which joins the C-peptide and the A-chain domains. We have previously cloned and characterized the exon-intron organization of the human PC2 gene (gene symbol PCSK2), localized this gene to human chromosome 20 band p11.2 by fluorescence in situ hybridization, and identified a simple tandem-repeat DNA polymorphism (STRP) in intron 2 of the form (CA)(n), suitable for genetic studies. Since non-insulin-dependent diabetes mellitus (NIDDM) is associated with increased secretion of proinsulin and proinsulin-like molecules, we conducted a case-control study to determine whether a genetic variation in PCSK2 might contribute to the development of NIDDM. The study population consisted of 152 Japanese NIDDM subjects and 102 normal healthy nondiabetic control subjects matched for age and body mass index. The subjects were genotyped at the STRP in intron 2, and the results indicated a significant difference (P = 0.004) in the overall allele frequency distribution between the two groups. The A1 allele was found more frequently in NIDDM than in nondiabetic subjects (11 vs, 4%, P = 0.0068). The NIDDM patients were divided into two subgroups according to the presence or absence of the A1 allele. There were no significant differences between these two subgroups with respect to age, sex, body mass index, family history of NIDDM, or current HbA(1c), fasting plasma glucose, and serum proinsulin levels. The 12 exons of the PC2 gene of 60 NIDDM subjects were screened for mutations that might explain the observed association using the technique of single-strand conformational polymorphism analysis. A single variant was noted in exon 1. One NIDDM subject was heterozygous for a G-->T substitution at 2 base pairs before the translational start site. This nucleotide substitution creates an in-frame methionine codon, which, if functional, would generate a protein with two methionine residues at its NH2-terminus rather than one. The functional consequences of such a change on the enzymatic properties of PC2 are unknown.

Introduction: Subclinical atherosclerosis ( SCA) measures in multiple arterial beds are heritable phenotypes that are associated with increased incidence of cardiovascular disease. We conducted a genome-wide association study ( GWAS) for SCA measurements in the community-based Framingham Heart Study. Methods: Over 100,000 single nucleotide polymorphisms ( SNPs) were genotyped ( Human 100K GeneChip, Affymetrix) in 1345 subjects from 310 families. We calculated sex-specific age-adjusted and multivariable-adjusted residuals in subjects tested for quantitative SCA phenotypes, including ankle-brachial index, coronary artery calcification and abdominal aortic calcification using multi-detector computed tomography, and carotid intimal medial thickness ( IMT) using carotid ultrasonography. We evaluated associations of these phenotypes with 70,987 autosomal SNPs with minor allele frequency >= 0.10, call rate >= 80%, and Hardy-Weinberg p-value >= 0.001 in samples ranging from 673 to 984 subjects, using linear regression with generalized estimating equations ( GEE) methodology and family-based association testing ( FBAT). Variance components LOD scores were also calculated. Results: There was no association result meeting criteria for genome-wide significance, but our methods identified 11 SNPs with p < 10(-5) by GEE and five SNPs with p < 10(-5) by FBAT for multivariable-adjusted phenotypes. Among the associated variants were SNPs in or near genes that may be considered candidates for further study, such as rs1376877 ( GEE p < 0.000001, located in ABI2) for maximum internal carotid artery IMT and rs4814615 ( FBAT p = 0.000003, located in PCSK2) for maximum common carotid artery IMT. Modest significant associations were noted with various SCA phenotypes for variants in previously reported atherosclerosis candidate genes, including NOS3 and ESRI. Associations were also noted of a region on chromosome 9p21 with CAC phenotypes that confirm associations with coronary heart disease and CAC in two recently reported genome-wide association studies. In linkage analyses, several regions of genome-wide linkage were noted, confirming previously reported linkage of internal carotid artery IMT on chromosome 12. All GEE, FBAT and linkage results are provided as an open-access results resource at http://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?id=phs000007. Conclusion: The results from this GWAS generate hypotheses regarding several SNPs that may be associated with SCA phenotypes in multiple arterial beds. Given the number of tests conducted, subsequent independent replication in a staged approach is essential to identify genetic variants that may be implicated in atherosclerosis.