Immunochemistry of human plasma high density lipoproteins. Radioimmunoassay of Apolipoprotein A-II

Journal Article · Mon Sep 01 04:00:00 EDT 1975 · Biochemistry, v. 14, no. 18, pp. 4127-4131

DOI:https://doi.org/10.1021/bi00689a033· OSTI ID:4074584

Mao, S J.T.; Gotto, Jr, A M; Jackson, R L

Apolipoprotein A-II (ApoA-II) is a major apoprotein of human plasma high density lipoproteins (HDL). The apoprotein has two identical chains of known amino acid sequence; the chains are linked by a single disulfide bond. In the present study, we have developed a specific radioimmunoassay for apoA-II that provides a convenient and reproducible method for measuring 10-100 ng of apoprotein. The assay was based on the competition of apoprotein with isotopically labeled [$sup 125$I]apoA-II. Dioxane (52 percent) was used to separate antibody bound [$sup 125$I]apoA-II from the free apoprotein. The assay has enabled us to begin studies directed toward mapping-out of the antigenic reactive regions of apoA-II. It has also allowed us to determine the interrelationship between the lipid-binding sites and the antigenic sites of the molecule. The antigenic reactivity of apoA-II was approximately the same in HDL and phospholipid-apoA-II complexes as that of the free apoprotein. However, succinylation of apoA-II was associated with a marked decrease in antigenic reactivity. (auth)

• Research Organization: Baylor Coll., Houston, TX
• Sponsoring Organization: USDOE
• NSA Number: NSA-33-015119
• OSTI ID: 4074584
• Journal Information: Biochemistry, v. 14, no. 18, pp. 4127-4131, Journal Name: Biochemistry, v. 14, no. 18, pp. 4127-4131; ISSN BICHA
• Country of Publication: United States
• Language: English

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