The sites of degradation of rat high-density-lipoprotein apolipoprotein E specifically labelled with O-(4-diazo-3-[125I]iodobenzoyl)sucrose.
O-(4-Diazo-3-[125I]iodobenzoyl)sucrose ([125I]DIBS), a novel labelling compound specifically designed to study the catabolic sites of serum proteins [De Jong, Bouma, & Gruber (1981) Biochem. J. 198, 45-51], was applied to study the tissue sites of degradation of serum lipoproteins. [125I]DIBS-labelled apolipoproteins (apo) E and A-I, added in tracer amounts to rat serum, associate with high-density lipoproteins (HDL) just like conventionally iodinated apo E and A-I. No difference is observed between the serum decays of chromatographically isolated [125I]DIBS-labelled and conventionally iodinated HDL labelled specifically in either apo E or apo A-I. When these specifically labelled HDLs are injected into fasted rats, a substantial [125I]DIBS-dependent 125I accumulation occurs in the kidneys and in the liver. No [125I]DIBS-dependent accumulation is observed in the kidneys after injection of labelled asialofetuin or human low-density lipoprotein. It is concluded that the kidneys and the liver are important sites of catabolism of rat HDL apo E and A-I.
D000818:Animals; D016632:Apolipoprotein A-I; D001054:Apolipoproteins A / Q000378:metabolism; D001057:Apolipoproteins E / Q000378:metabolism*; D001665:Binding Sites; D002850:Chromatography, Gel; D066298:In Vitro Techniques; D007463:Iodobenzoates; D007668:Kidney / Q000378:metabolism; D008075:Lipoproteins, HDL / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013347:Subcellular Fractions / Q000201:enzymology / Q000378:metabolism
D016632:Apolipoprotein A-I; D001054:Apolipoproteins A; D001057:Apolipoproteins E; D007463:Iodobenzoates; D008075:Lipoproteins, HDL; C044133:O-(4-diazo-3-iodobenzoyl)sucrose