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The A-I Milano variant of apolipoprotein A-I (A-IM), by virtue of its Arg-173----Cys substitution, is capable of forming a disulfide bond with the 77-amino-acid apolipoprotein A-II polypeptide (A-IIS) as well as with itself to produce dimers, A-IM/A-IIS and A-IM/A-IM, respectively. A-I-containing lipoproteins (Lp): particles with A-II (Lp(A-I with A-11)) and particles without A-II (Lp(A-I without A-II)) in the plasma of two nonhyperlipidemic A-IM carriers were investigated to determine the effect of A-IM on these lipoproteins. Despite the existence of abnormal apolipoprotein dimers and the unusually low HDL cholesterol (17 and 14 mg/dl), A-I (67 and 75 mg/dl), and A-II (18 and 18 mg/dl) levels in the two carriers, the plasma A-I of the carriers was distributed between Lp(A-I with A-II) and Lp(A-I without A-II) in a proportion comparable to that observed in normals. As expected, A-IM/A-IIS mixed dimer was found in carrier Lp(A-I with A-II). However, A-IM/A-IM dimer was located almost exclusively in carrier Lp(A-I without A-II). Chemical (dimethylsuberimidate) crosslinking of the protein moieties of the major subpopulations of Lp(A-I with A-II) and Lp(A-I without A-II) of normal and A-IM carriers showed that Lp(A-I with A-II), which is located predominantly in the 7.8-9.7 nm interval ((HDL2a + 3a + 3b)gge), had an apparent protein molecular weight equivalent to two molecules of A-I and one to two molecules of A-II per particle. Most of the Lp(A-I without A-II) particles, located predominantly in the size intervals of 9.7-12.9 nm (designated (HDL2b)gge) and 8.2-8.8 nm (HDL3a)gge) had protein moieties exhibiting a molecular weight equivalence predominantly of four and three molecules of A-I, respectively. A small quantity of particles with apparent protein content of two molecules of A-I in the 7.2-8.2 nm interval ((HDL3b + 3c)gge) was also detected. These studies showed that in nonhyperlipidemic A-IM carriers, the occurrence of apolipoprotein dimers had not markedly affected the protein stoichiometry of Lp(A-I with A-II) and Lp(A-I without A-II).
M C Cheung, and
A V Nichols, and
P J Blanche, and
E L Gong, and
G Franceschini, and
C R Sirtori
December 1983,
Schweizerische medizinische Wochenschrift,
M C Cheung, and
A V Nichols, and
P J Blanche, and
E L Gong, and
G Franceschini, and
C R Sirtori
March 1991,
Journal of lipid research,
M C Cheung, and
A V Nichols, and
P J Blanche, and
E L Gong, and
G Franceschini, and
C R Sirtori
November 1980,
The Journal of clinical investigation,
M C Cheung, and
A V Nichols, and
P J Blanche, and
E L Gong, and
G Franceschini, and
C R Sirtori
January 1986,
Methods in enzymology,
M C Cheung, and
A V Nichols, and
P J Blanche, and
E L Gong, and
G Franceschini, and
C R Sirtori
May 2005,
American journal of critical care : an official publication, American Association of Critical-Care Nurses,
M C Cheung, and
A V Nichols, and
P J Blanche, and
E L Gong, and
G Franceschini, and
C R Sirtori
October 1995,
Current opinion in lipidology,
M C Cheung, and
A V Nichols, and
P J Blanche, and
E L Gong, and
G Franceschini, and
C R Sirtori
September 1993,
Diabetes,
M C Cheung, and
A V Nichols, and
P J Blanche, and
E L Gong, and
G Franceschini, and
C R Sirtori
January 1986,
Methods in enzymology,
M C Cheung, and
A V Nichols, and
P J Blanche, and
E L Gong, and
G Franceschini, and
C R Sirtori
January 1986,
Methods in enzymology,
M C Cheung, and
A V Nichols, and
P J Blanche, and
E L Gong, and
G Franceschini, and
C R Sirtori
May 1985,
Journal of lipid research,
