Lipoproteins (d = 1.05-1.12 g/ml) were obtained from pooled serum by density gradient ultracentrifugation and used as a source for isolation of apolipoprotein (a) (apo(a]. It was found that both these lipoproteins and purified apo(a) possess negligible amidolytic and proteolytic activity. After preincubation of lipoproteins and apo(a) with collagen-Sepharose, the increase in enzymatic activity was observed. The activation of purified apo(a) also occurred upon its storage in the cold. After two week storage at 7 degrees C, the amidase activity, as measured by splitting of the substrate D-Pro-Phe-Arg-pNA, was increased from 0.009 U/mg to 0.85 U/mg. The amidase activity was completely inhibited by phenylmethylsulfonyl fluoride (10(-3) M) and by soybean trypsin inhibitor (10(-5) M); it was not inhibited by aprotinin (10(-6) M). Activated apo(a) did not split azocasein but converted plasma prekallikrein to kallikrein and degraded apolipoprotein B-100.
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http://dx.doi.org/10.1016/0006-291x(90)91182-r | DOI Listing |
J Lipid Res
December 2024
Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA; Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH, USA; Department of Neurology, Oregon Health and Science University, Portland, OR, USA. Electronic address:
The ability of high-density lipoprotein (HDL) to promote cellular cholesterol efflux is a more robust predictor of cardiovascular disease protection than HDL-cholesterol levels in plasma. Previously, we found that lipidated HDL containing both apolipoprotein A-I (APOA1) and A-II (APOA2) promotes cholesterol efflux via the ATP-binding cassette transporter (ABCA1). In the current study, we directly added purified, lipid-free APOA2 to human plasma and found a dose-dependent increase in whole plasma cholesterol efflux capacity.
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
October 2024
Clinical Biochemistry Department. Vall d'Hebron University Hospital. Clinical Biochemistry, drug delivery and therapy Research Group, Vall d'Hebrón Research Institute (VHIR), Vall d'Hebron Barcelona Hospital Campus, 08035 Barcelona, Spain.
Apolipoprotein A-I (ApoA-I), one of the most abundant proteins in plasma and the major protein component of high-density lipoprotein (HDL), is naturally found in several proteoforms; two of them are ProApoA-I and mature ApoA-I. These two proteoforms of ApoA-I coexist in biological samples and differ only in their N-terminal end. Virtually, the only way to differentiate them is by detecting the proteoform-specific N-terminal proteolytic peptides (RHFWQQDEPPQSPWDR and DEPPQSPWDR, respectively) using liquid chromatography in multiple reaction monitoring mode mass spectrometry (LC-MRM-MS).
View Article and Find Full Text PDFJ Allergy Clin Immunol
September 2024
Department of Allergy and Immunology, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain; Faculty of Medicine, Universidad Alfonso X el Sabio (UAX), Villanueva de la Cañada, Spain. Electronic address:
Background: Growing evidence demonstrates the importance of high- and low-density lipoprotein cholesterol in certain immune and allergy-mediated diseases.
Objective: This study aimed to evaluate levels of high- and low-density lipoprotein cholesterol and apolipoproteins A1 and B in sera from a cohort of patients presenting with hypersensitivity reactions. We further assessed the function of high-density lipoprotein particles as well as their involvement in the molecular mechanisms of anaphylaxis.
Pharmaceuticals (Basel)
March 2024
Raydel Research Institute, Medical Innovation Complex, Daegu 41061, Republic of Korea.
The present study compares sugarcane-wax purified policosanols sourced from Cuba (Raydel) and China (BOC Sciences) and utilized following the synthesis of reconstituted high-density lipoproteins (rHDL). The two policosanols exhibited distinctly different ingredient ratios of long-chain aliphatic alcohols, particularly 1-octacosanol (C28) and 1-tetratriacotanol (C34). After synthesizing rHDL with apolipoprotein A-I (apoA-I), the two policosanols bound well with phospholipid and apoA-I to form the discoidal rHDL.
View Article and Find Full Text PDFJ Biochem
May 2024
Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan.
High-density lipoprotein (HDL) transports excess cholesterol from peripheral tissues back to the liver, and plasma HDL levels are inversely related to cardiovascular disease incidence. ATP-binding cassette A1 (ABCA1) is a member of the ABC protein superfamily, and generates nascent HDL, which consists of several hundreds of phospholipids and cholesterol wrapped by apolipoprotein A-I (apoA-I). However, it remains unclear whether cholesterol is a transport substrate of ABCA1.
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