Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The passage of radioactive apolipoproteins into lymph draining the foot was investigated in two men, each given a single intravenous injection of low-density lipoprotein containing 131I-labelled apoprotein B and of very-low-density lipoprotein containing 125I-labelled apoprotein A and apoprotein C. 2. Protein-bound 125I and 131I appeared in the lymph of both subjects. Immunoelectrophoresis of lymph lipoproteins against anti-(high-density lipoprotein) and anti-(low-density lipoprotein) showed the presence of apo-high-density lipoprotein and apo-low-density lipoprotein with faster mobilities than plasma high-density and low-density lipoprotein respectively. Most of the protein-bound 131I in lymph was recovered in the precipitin line formed by the apoprotein B-containing lipoprotein after immunoelectrophoresis. Polyacrylamide gel electrophoresis of the lymph lipoprotein fraction showed the presence of 125I-containing bands with mobilities similar to those of the apoprotein A of high-density lipoprotein and of three of the fast-moving C apoproteins. 3. These results suggest that most, if not all, of the apoproteins of plasma lipoproteins reach the interstitial fluids and that some lipoproteins undergo modification during their passage into peripheral lymph.
Clin Sci Mol Med 1975 Nov
PMID:Observations on the passage of apoproteins from plasma lipoproteins into peripheral lymph in two men. 17 78

1. The metabolism in vivo and in vitro of an abnormal low-density lipoprotein (LDL) obtained from a patient with an inherited form of hypercholesterolaemia was compared with that of LDL obtained from a normal subject. 2. The rates of turnover of the apoprotein of the two types of LDL in a normal subject, and their uptake and catabolism by normal lymphocytes in vitro, were similar. 3. It is concluded that the abnormal behaviour of the patient's LDL may not be due to an abnormality in the apoprotein component.
Clin Sci Mol Med 1976 Nov
PMID:The metabolism in vivo and in vitro of plasma low-density lipoprotein from a subject with inherited hypercholesterolaemia. 18 27

A noncovalent complex of the apoprotein (1-104) and cyanogen bromide heme fragment containing residues 1 to 65, (1-65) H, has been prepared from horse heart cytochrome c. Conditions under which the redundant portions of the ferrous complex can be removed by limited trypsin digestion have been devised. The complementing fragments have been isolated from the derived complexes and four apofragments and one heme fragment have been identified in the amino acid sequence of cytochrome c. They are (39-104), (40-104), (54-104), (56-104), and (1-53)H. The formation of an ordered ferric complex composed of one heme fragment and one apofragment for the cases (1-53)H (39-104), (1-53)H-(40-104), (1-53)H-(54-104), and (1-53)H-(56-104) has been demonstrated by the quenching of the tryptophan 59 fluorescence and the regain of biological activity in a cytochrome b2 assay. The apparent dissociation constant has been estimated as less than 3 X 10(-7) M in all the aforementioned cases. Thus, the region (between residues 38 and 57) of the amino acid sequence permissible for cleavage without disruption of the ordered structure indicated by the present in vitro experiments corresponds to that (between residues 38 and 57) evolutionally deleted in the three-dimensional structure of Pseudomonas aeruginosa cytochrome c551 discovered by Dickerson et al. (Dickerson, R.E., Timkovich, R., and Almassy, R.J. (1976) J. Mol. Biol. 100, 473-491).
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PMID:Formation of a biologically active, ordered complex from two overlapping fragments of cytochrome c. 19 Feb 31

1. The non-steady-state turnover of low-density lipoprotein (LDL), labelled in its apoprotein moiety (apo-B) with 131I, was determined in four patients with familial hypercholesterolaemia, three of them homozygotes. 2. The fractional and absolute catabolic rates (FCR and ACR) of LDL-apo-B were determined by relating the excretion of radioactivity, measured in urine in vitro and by whole-body counter in vivo, to plasma radioactivity and to LDL specific radioactivity respectively. 3. The FCR remained relatively constant, even after marked reduction of LDL pool size by means of plasma exchange. This confirms the existence of an intrinsic defect in LDL catabolism in familial hypercholesterolaemia. 4. LDL-apo-B synthesis, determined by summing the ACR and the daily increment in plasma LDL, was much higher in the three homozygotes than in the one heterozygote, in whom the synthetic rate was normal. 5. These results illustrate the usefulness of combining plasma exchange and whole-body radioactivy counting as a means of examining the relationship between the turnover and pool size of a 131I-labelled protein, such as LDL.
Clin Sci Mol Med 1977 Apr
PMID:Non-stedy-state studies of low-density-liproprotein turnover in familial hypercholesterolaemia. 19 66

1. The transport of apoprotein B from the lipoprotein of plasma into the lipoproteins of lymph draining the foot has been studied in four men with type III hyperlipoproteinaemia. 2. Three subjects were given autologous 125I-labelled very-low-density lipoprotein (VLDL) and 131I-labelled low-density lipoprotein (LDL) by intravenous injection; the fourth was given autologous 125I-labelled VLDL and 131I-labelled intermediate-density lipoprotein (IDL) plus LDL. 3. The 125I/131I ratios in serum and lymph apoprotein B, and the 125I and 131I specific radioactivities of apoprotein B in VLDL, IDL and LDL from serum and lymph, indicate that apoprotein B in the circulating VLDL can reach peripherallymph without the intermediacy of circulating LDL.
Clin Sci Mol Med 1977 Sep
PMID:The passage of apoproteins from plasma lipoproteins into the lipoproteins of peripheral lymph in man. 19 96

Mucolipidosis II (I-cell disease) and Mucolipidosis III (ML III) are inherited disorders in which the molecular defect may involve an abnormality in a common post-translational modification step (possibly glycosylation) shared by lysosomal hydrolases. We tested whether such an alteration might be a generalized defect in glycoprotein biosynthesis and, thus, be reflected in an abnormal carbohydrate composition of non-lysosomal glycoproteins. The apoprotein of low density lipoprotein (apo-LDL) and immunoglobulin G (IgG) were purified to apparent homogeneity. Gas liquid chromatographic (glc) analysis of the carbohydrate content of these glycoproteins from ML II, ML III and normal sera revealed no differences in the relative ratios and total amounts of mannose, galactose, N-acetylglucosamine and sialic acid. These results suggest that if the postulated post-translational defect in these disorders involves changes in carbohydrate composition, it is not a general defect in glycosylation and may be specific for lysosomal hydrolases.
Mol Cell Biochem 1978 Oct 13
PMID:Carbohydrate composition of purified serum glycoproteins in mucolipidosis II and mucolipidosis III. 21 98

1. Fourteen cytoplasmic mutants of Saccharomyces cerevisiae with a specific deficiency of cytochrome b have been studied. The mutations have been shown to occur in two separate genetic loci, COB 1 and COB 2. These loci can be distinguished by mit- X mit- crosses. Pairwise crosses of cytochrome b mutants belonging to different loci yield 4-6% wild type recombinants corresponding to recombinational frequencies of 8-12%. In intra-locus crosses, the recombinational frequencies range from 1% to less than 0.01%. The two loci can also be distinguished by mit- X rho- crosses. Twenty rho- testers have been isolated of which ten preferentially restore mutations in COB 1 and ten others in COB 2. 2. The COB 1 and COB 2 loci have been localized on mitochondrial DNA between the two antibiotic resistance loci OLI 1 and OLI 2 in the order OLI 2-COB 2-COB 1-OLI 1. The results of mit- X mit- and mit- X rho- crosses have also been used to map the cytochrome b mutations relative to each other. The maps obtained by the two independent methods are in good agreement. 3. Mutations in COB 1 have been found to be linked to the OLI1 locus in some but not in other strains of S. cervisiae. This evidence suggests that there may be a spacer region between the two loci whose length varies from strain to strain. 4. Two mutations in COB 2 have been found to cause a loss of a mitochondrial translation product corresponding to the cytochrome b apoprotein. Instead of the wild type protein the mutants have a new low-molecular weight product which is probably a fragment of cytochrome b. The fact that the mutations revert suggests that they are nonsense mutations in the structural gene of cytochrome b.
Mol Gen Genet 1976 Nov 24
PMID:Assembly of the mitochondrial membrane system. XVIII. Genetic loci on mitochondrial DNA involved in cytochrome b biosynthesis. 79 70

Mammalian liver contains two types of galactose receptors, specific for Kupffer or parenchymal cells. Because galactose-specific receptors are largely confined to the liver, galactose-bearing carriers are promising vehicles for the specific delivery of drugs to liver cells. In the present study, high density lipoprotein (HDL), a spherical particle with a diameter of 10 nm, in which a variety of lipophilic drugs can be incorporated, was provided with galactose residues by reductive lactosamination. After injection into rats, lactosylated 125I-HDL was rapidly cleared from the plasma (half-life, less than 1 min). Ten minutes after injection, the liver contained about 95% of the dose, whereas only small amounts of radioactivity were found in other tissues. The hepatic uptake was inhibited by preinjection with N-acetylgalactosamine, which indicates that the hepatic recognition sites are galactose specific. Subcellular fractionation of the liver indicated that recognition of lactosylated HDL is followed by internalization and degradation of the apoprotein in the lysosomes. Liver cells were isolated at 10 min after injection of lactosylated 125I-HDL, and it was found that uptake occurs almost exclusively by parenchymal cells. These cells contained about 98% of the hepatic radioactivity. The liver uptake of the lipid moiety of lactosylated HDL, labeled with [3H]cholesteryl oleate, was identical to that of the 125I-labeled apoproteins, which indicates that the particle is taken up as a unit. Thus, lactosylated HDL is taken up rapidly and selectively by parenchymal liver cells, and it appears that it might be a very effective vehicle for the specific delivery of lipophilic drugs to these cells.
Mol Pharmacol 1992 Feb
PMID:Lactosylated high density lipoprotein: a potential carrier for the site-specific delivery of drugs to parenchymal liver cells. 131 13

Previous studies showed that apolipoprotein-E (apoE) mRNA is regulated in rat adrenal gland by treatments that alter adrenal gland cholesterol content and steroidogenesis. In the present study cell types expressing apoE mRNA were determined by in situ hybridizations using an [alpha-35S]UTP-labeled RNA probe. Autoradiographic grains were counted to compare apoE expression in adrenal glands from control and experimentally treated animals. In control adrenal gland, zona (z.) fasciculata and z. reticularis exhibited the highest level of apoE mRNA expression, with lower levels in z. glomerulosa and medulla. Dexamethasone (DEX) treatment selectively increased apoE mRNA 3-fold in outer z. fasciculata, but not in other adrenal zones. ApoE mRNA expression appeared to be lower in adrenal glands from 4-aminopyrazolopyrimidine-treated rats, in that differences among adrenal gland zones were abolished. DEX treatment increased adrenal gland cholesteryl ester and oil red O staining in z. fasciculata cells in which the apoE mRNA concentration was increased as well as in other cortical cells in which apoE mRNA was unchanged. Aminoglutethimide administration led to a large increase in oil red O staining throughout the cortex, including z. fasciculata, without affecting apoE mRNA expression. These data suggest that adrenal gland apoE mRNA expression is not closely coupled to cellular cholesterol concentrations. Increased apoE mRNA expression in z. fasciculata of DEX-treated animals suggests an inverse relationship between apoE mRNA concentration and the level of steroidogenesis. This result is consistent with the proposal that apoE may play a role in regulating the utilization of cholesterol for steroid production.
Mol Endocrinol 1992 Feb
PMID:Differential regulation of apolipoprotein-E messenger RNA in zona fasciculata cells of rat adrenal gland determined by in situ hybridization. 137 19

We have isolated and sequenced overlapping genomic and cDNA clones encoding the apoprotein of a potato phytochrome. Based on the deduced amino acid sequence, which shows 77% identity to the Arabidopsis phyB and 50% identity to the potato phyA open reading frame, we suggest that these clones encode phyB phytochrome. However, the size of the deduced open reading frame of 1133 amino acids is smaller than the size of the other two phyB open reading frames characterized so far in higher plants, which contain 1171 or 1187 amino acids. The intron/exon structure within the coding region is conserved in phyA and phyB genes of various species. Southern blot analysis indicates that potato phyB is a single-copy gene. PhyB mRNA levels do not differ among different organs or different light regimes. Transcription initiation starts from two different start points which are 63 bp apart.
Plant Mol Biol 1992 Nov
PMID:Isolation and characterization of a cDNA-clone coding for potato type B phytochrome. 145 Mar 76


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