TY - JOUR
T1 - Peripheral synthesis and isoform distribution of dog apoprotein E. An in vivo approach
AU - Dory, L.
AU - Boquet, L. M.
AU - Tate, C. R.
AU - Sloop, C. H.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1986
Y1 - 1986
N2 - Purified dog plasma apo-E is composed of four major isoforms with the following pI values: 5.40, 5.31, 5.26, and 5.22. Treatment with neuraminidase suggests that the multiple forms are due to progressive sialation. The acidic isoforms (pI = 5.22 and less), rarely detectable in plasma lipoprotein samples (except in the d < 1.05 g/ml fraction of cholesterol-fed dogs), are present in high density lipoprotein fraction I (HDL(I)) of cholesterol-fed dogs, a lipoprotein recently described (Dory, L., Boquet, L.M., Hamilton, R.L., Sloop, C.H., and Roheim, P.S. (1985) J. Lipid Res. 26 519-527). Apo-E(s0) (the most basic isoform) is a major constituent of the plasma d < 1.05 g/ml fraction, but it is usually only a minor component of other plasma or interstitial fluid lipoproteins. This is likely a reflection of the prolonged residence time of a specific lipoprotein species in this density range, resulting in more extensive desialation. Peripheral apo-E synthesis has been measured under in vivo conditions using a hindlimb cannulation of the lymphatics and collection of prenodal peripheral lymph. Following injection of [3H]leucine or [35S]methionine into the dorsal skin of the toes, the specific activity of the interstitial fluid apo-E far exceeded that of plasma apo-E at all time points examined. Incorporation was measurable 30 min after the isotope injection and peaked at 150 min in control dogs and between 120-150 min in cholesterol-fed dogs. The rate of peripheral synthesis of apo-E in cholesterol-fed dogs appeared to be twice that of control dogs. The newly synthesized and secreted apo-E preferentially associated with the disc-shaped HDL(I) of the interstitial fluid; less than 15% of the apo-E-associated radioactivity was recovered in the d<1.05 g/ml fraction, despite the fact that this fraction contains well over 50% of the total interstitial fluid apo-E mass. The newly secreted, HDL(I)-associated apo-E can be converted by neuroaminidase into apo-E(s0).
AB - Purified dog plasma apo-E is composed of four major isoforms with the following pI values: 5.40, 5.31, 5.26, and 5.22. Treatment with neuraminidase suggests that the multiple forms are due to progressive sialation. The acidic isoforms (pI = 5.22 and less), rarely detectable in plasma lipoprotein samples (except in the d < 1.05 g/ml fraction of cholesterol-fed dogs), are present in high density lipoprotein fraction I (HDL(I)) of cholesterol-fed dogs, a lipoprotein recently described (Dory, L., Boquet, L.M., Hamilton, R.L., Sloop, C.H., and Roheim, P.S. (1985) J. Lipid Res. 26 519-527). Apo-E(s0) (the most basic isoform) is a major constituent of the plasma d < 1.05 g/ml fraction, but it is usually only a minor component of other plasma or interstitial fluid lipoproteins. This is likely a reflection of the prolonged residence time of a specific lipoprotein species in this density range, resulting in more extensive desialation. Peripheral apo-E synthesis has been measured under in vivo conditions using a hindlimb cannulation of the lymphatics and collection of prenodal peripheral lymph. Following injection of [3H]leucine or [35S]methionine into the dorsal skin of the toes, the specific activity of the interstitial fluid apo-E far exceeded that of plasma apo-E at all time points examined. Incorporation was measurable 30 min after the isotope injection and peaked at 150 min in control dogs and between 120-150 min in cholesterol-fed dogs. The rate of peripheral synthesis of apo-E in cholesterol-fed dogs appeared to be twice that of control dogs. The newly synthesized and secreted apo-E preferentially associated with the disc-shaped HDL(I) of the interstitial fluid; less than 15% of the apo-E-associated radioactivity was recovered in the d<1.05 g/ml fraction, despite the fact that this fraction contains well over 50% of the total interstitial fluid apo-E mass. The newly secreted, HDL(I)-associated apo-E can be converted by neuroaminidase into apo-E(s0).
UR - http://www.scopus.com/inward/record.url?scp=0022574422&partnerID=8YFLogxK
M3 - Article
C2 - 3941102
AN - SCOPUS:0022574422
SN - 0021-9258
VL - 261
SP - 811
EP - 816
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 2
ER -