The role of human glutathione S-transferase isoenzymes in the formation of glutathione conjugates of the alkylating cytostatic drug thiotepa

Nonenzymatic and glutathione S-transferase (GST) catalyzed glutathione (GSH) conjugation has been postulated as a mechanism by which alkylating cytostatic drugs can be inactivated intracellularly. In this study, we describe studies on the glutathione-dependent biotransformation of thiotepa (tris(1-aziridinyl)phosphine sulfide), a trifunctional...

The role of the lysyl binding site of tissue-type plasminogen activator in the interaction with a forming fibrin clot

To describe the role of the lysyl binding site in the interaction of tissue-type plasminogen activator (t-PA, FGK1K2P) with a forming fibrin clot, we performed binding experiments with domain deletion mutants GK1K2P, K2P, and the corresponding point mutants lacking the lysyl binding site in the absence and the presence of ε-amino caproic acid ...

Molecular basis for fibrinogen Dusart (Aα 554 Arg → Cys) and its association with abnormal fibrin polymerization and thrombophilia

The molecular defect in the abnormal fibrinogen Dusart (Paris V) that is associated with thrombophilia was determined by sequence analysis of genomic DNA that had been amplified using the polymerase chain reaction. The propositus was heterozygous for a single base change (C → T) in the Aα- chain gene, resulting in the amino acid substitution Aα...

Low density lipoprotein receptor internalizes low density and very low density lipoproteins that are bound to heparan sulfate proteoglycans via lipoprotein lipase

It has previously been shown that lipoprotein lipase (LPL) enhances the binding of low density lipoproteins (LDL) and very low density lipoproteins (VLDL) to HepG2 cells and fibroblasts, up to 80-fold. This increase in binding is LDL receptor-independent and is due to a bridging of LPL between extracellular heparan sulfate proteoglycans (HSPG)...

Inefficient degradation of triglyceride-rich lipoprotein by HepG2 cells is due to a retarded transport to the lysosomal compartment

Binding studies at 37 °C showed that lipoprotein lipase-treated very low density lipoproteins (LPL-VLDL) and very low density lipoproteins (VLDL), once taken up via the low density lipoprotein (LDL) receptor, are poorly degraded by HepG2 cells as compared with LDL. Determination of the initial endocytotic rate for LPL-VLDL and VLDL as compared...

Mechanisms of tissue-type plasminogen activator (tPA) clearance by the liver

Chemicals/CAS: mannose receptor; Mannose, 31103-86-3; PLAT protein, human; Receptors, Cell Surface; Receptors, Immunologic; Recombinant Proteins; Tissue Plasminogen Activator, EC 3.4.21.68.

In vitro binding of estrogens by dietary fiber and the in vivo apparent digestibility tested in pigs

Within the framework of experiments related to the association between dietary fiber and breast cancer an in vitro test system was used to study the binding of estrogens to various fibers (e.g. cholestyramin, lignin and cellulose) and fiber sources (e.g. wheat bran, cereals, seeds and legumes). Furthermore, the in vivo apparent digestibility of...

Visualization of proteases within a complex sample following their selective retention on immobilized bacitracin, a peptide antibiotic

A method for the visualization of individual proteases within a complex biological sample is described. In a single chromatographic step, proteases can be separated from other biomolecules by selective binding to immobilized bacitracin, a peptide antibiotic. Following desorption, proteases may be separated by SDS-polyacrylamide gel...

Interactions of halogenated industrial chemicals with transthyretin and effects on thyroid hormone levels in vivo

Previous results in experimental systems have suggested that hydroxylated PCBs may decrease thyroid hormone levels through associative interaction with transthyretin. In the present paper it was investigated whether this property was also shared by various industrial chemicals, mainly pesticides. In total, 65 compounds from 12 chemical groups...

Binding and degradation of tissue-type plasminogen activator by the human hepatoma cell line Hep G2

In this study, binding and degradation of tissue-type plasminogen activator (t-PA) by the human hepatoma cell line Hep G2 was investigated. Binding at 4°C was time-dependent and reached a maximum after ca. 2 hours. Scatchard analysis of saturation experiments showed about 170,000 high affinity binding sites for t-PA per cell with an apparent Kd...

Identification of a reversible inhibitor of plasminogen activators in blood plasma

Inhibition of tissue-type plasminogen activator (t-PA) by pooled plasma could be ascribed for only 60% to the endothelial cell type PA inhibitor. The residual inhibition is ascribed to a so-far undescribed plasma component present at 0.2 nmol/l. This component shows reversible binding to t-PA with an apparent K(i) of 10 pmol/l (does not hinder t...

The metabolism in vitro of human low-density lipoprotein by the human hepatoma cell line Hep G2

The human hepatoma cell line Hep G2 was studied with respect to metabolism of human low-density lipoprotein (LDL). The Hep G2 cells bind, take up and degrade human LDL with a high-affinity saturable and with a low-affinity non-saturable component. The high-affinity binding possesses a K(D) of 25 nM-LDL and a maximal amount of binding of about 70...

Anticoagulant and calcium-binding properties of high molecular weight derivatives of human fibrinogen (plasmin fragments Y)

The present study was undertaken as a step to delineate further the localization of the calcium-binding sites in fibrinogen and to assess the anticlotting properties of fibrinogen degradation products. To this purpose, fragments Y were prepared by plasmin digestion of human fibrinogen in the presence of added Ca2+, and purified. We found that,...

Calcium-binding properties of human fibrin(ogen) and degradation products

Here the results obtained with human fibrinogen and its degradation products are reported. Our results differ from those obtained in (9) but strongly support model suggested earlier by us for Ca2(+)-binding by rat fibrinogen. Chemicals/CAS: calcium, 7440-70-2; fibrin, 9001-31-4; fibrinogen, 9001-32-5; Calcium, 7440-70-2; Fibrin, 9001-31-4;...

Ca binding of rat fibrinogen and fibrin(ogen) degradation products

The authors studied the binding of Ca to rat fibrinogen and plasmic fibrin(ogen) degradation products by means of equilibrium dialysis with special reference to the protective effect of Ca2+ in the plasmic degradation of fibrinogen. Direct binding studies demonstrate that rat fibrinogen and the plasmic degradation products D(cate) and D-dimer...

Differential binding of methyl benzimidazol 2 yl carbamate to fungal tubulin as a mechanism of resistance to this antimiotic agent in mutant strains of Aspergillus nidulans

Chemicals/CAS: benomyl, 17804-35-2; carbon 14, 14762-75-5; colchicine, 64-86-8; fuberidazole, 3878-19-1; griseofulvin, 126-07-8; mebendazole, 31431-39-7; melatonin, 73-31-4; nocodazole, 31430-18-9; parbendazole, 14255-87-9; podophyllotoxin, 518-28-5; tiabendazole, 148-79-8; vinblastine, 865-21-4; Benzimidazoles; Carbamates; Colchicine, 64-86-8;...

The binding of sarin in the blood plasma of the rat

Sephadex filtration of serum from rats 10 min after injection of 50 μg/kg of 32P-sarin demonstrated that about 70 per cent of the radioactivity present in the serum was attached to molecules with a molecular weight above 10,000. Incubation of samples of this serum with oximes caused a decrease in the amounts of 32P attached to the large...

The influence of triorthocresylphosphate on the distribution of 32P in the body of the rat after the injection of 32P-sarin

The ChE- and AE- activities and the 32P-concentration of the plasma from rats 1 and 24 hr after s.c. injection of 32P-sarin (200 μg kg) were measured. One hr after the injection the ChE was inhibited to approx. 10 per cent and the AE to 40-50 per cent; 23 hr later 50 per cent of the ChE activity was found to be restored and the AE had recovered...