Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human factor VIII/von Willebrand factor protein containing 120 +/- 12 nmol of sialic acid and 135 +/- 13 nmol of galactose/mg of protein was digested with neuraminidase. The affinity of native factor VIII/von Willebrand factor and its asialo form for the hepatic lectin that specifically binds asialoglycoproteins was assessed from in vitro binding experiments. Native factor VIII/von Willebrand factor exhibited negligible affinity while binding of the asialo derivative was comparable to that observed for asialo-alpha1-acid glycoprotein. Incubation of asialo-factor VIII/von Willebrand factor with Streptococcus pneumoniae beta-galactosidase removed only 62% of the galactose but abolished binding to the purified hepatic lectin. When the asialo derivative was incubated with purified beta-D-galactoside alpha2 leads to 6 sialyltransferase and CMP-[14C]NeuAc, only 61% of the galactose incorporated [14C]NeuAc. From the known specificites of these enzymes, it is concluded that galactose residues important in lectin binding are present in a terminal Gal/beta1 leads to 4GlcNAc sequence on asialo-factor VIII/von Willebrand factor. The relative ristocetin-induced platelet aggregating activity of native, asialo-, and agalacto-factor VIII/von Willebrand factor was 100:38:12, respectively, while procoagulant activity was 100:100:103.
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PMID:Carbohydrate on human factor VIII/von Willebrand factor. Impairment of function by removal of specific galactose residues. 10 Apr 92

A recombinant human von Willebrand factor (vWF) cDNA fragment library was constructed in lambda gt11 for the localization of anti-vWF monoclonal antibody epitopes. Twelve of 21 monoclonal antibodies screened identified epitopes expressed in lambda gt11 as beta-galactosidase fusion proteins. By sequence analysis, these antigenic determinants were localized to segments ranging from 17 to 105 amino acids in length. Four epitopes apparently shared by more than one antibody were identified, suggesting the presence of immuno-dominant epitopes within vWF. Monoclonal antibody C3, which blocks factor VIII (FVIII) binding to vWF, bound to the same epitope previously identified by a second monoclonal antibody which also blocks this function, suggesting that this region may be at or near the vWF/FVIII binding domain. Three antibodies recognize the same region within the vWF A2 repeat. Mutations near this region appear to be responsible for Type IIA von Willebrand's disease. The co-localization of these antibodies suggests that this domain might be exposed on the surface of vWF, consistent with its apparent increased sensitivity to plasma proteases.
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PMID:Fine mapping of monoclonal antibody epitopes on human von Willebrand factor using a recombinant peptide library. 137 14

The carbohydrate moiety of the factor VIII/von Willebrand (vW) factor protein is important in the expression of vW factor activity and the intravascular survival of the protein. Studies of normal human factor VIII/vW factor protein indicate that there is a requirement of a full complement of penultimate galactose for the maintenance of a normal multimeric structure. Release of penultimate galactose by beta-galactosidase or modification by galactose oxidase results in loss of the largest molecular weight multimers and increased numbers of intermediate and smaller multimers. In contrast, terminal galactose on the factor VIII/vW factor protein does not appear to play a significant role in the maintenance of the multimer organization. The abnormalities in multimeric structure and molecular size were demonstrated by NaDodSO4/polyacrylamide/agarose gel electrophoresis, NaDodSO4/glyoxyl-agarose electrophoresis, and sucrose density ultracentrifugation. These studies indicate that the penultimate galactose plays a role in the maintenance of the largest multimers of the factor VIII/vW factor protein. This may explain why, in some patients with variant forms of vW disease, a carbohydrate abnormality also may affect the multimeric structure of the plasma factor VIII/vW factor protein.
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PMID:Role of carbohydrate in multimeric structure of factor VIII/von Willebrand factor protein. 660 5

Invasion-inhibiting factor 2 (IIF-2) and its albumin conjugate have been reported to inhibit spontaneous metastasis of highly metastatic cancer cells with no effect on primary tumor growth. To confirm the inhibitory effects of the IIF-2 conjugate on tumor invasion and spontaneous metastasis, we administered the conjugate intra-peritoneally (i.p.) to female nude mice bearing transplanted tumors with MKL-4 cells, which are MCF-7 human breast cancer cells cotransfected with fibroblast growth factor 4 and lacZ. Neither 10 nor 20 mg/kg doses of the conjugate caused any inhibition of primary tumor growth, but 20 mg/kg significantly inhibited tumor invasion and spontaneous metastasis. Tumor invasion was measured by a novel computer-assisted image analysis. Spontaneous microscopic metastases into lymph nodes and distant organs were measured by whole organ staining for beta-galactosidase activity and observed with a dissecting microscope. The dose of 10 mg/kg significantly inhibited tumor invasion but not metastasis. Interestingly, the number of factor VIII-positive microvessels in the tumors was not reduced by treatment at either dose level. These findings suggest that the anti-invasive effect of the IIF-2 conjugate may reduce both lymphatic and hematogenous metastases in this MKL-4 metastasis model without affecting angiogenesis.
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PMID:Invasion-inhibiting factor 2-albumin conjugate inhibits invasion and spontaneous metastasis of MKL-4 human breast cancer cells transplanted into female nude mice. 860 32

Development of in utero gene transfer approaches may provide therapies for genetic disorders with perinatal morbidity. In hemophilia A, prenatal and postnatal bleeding may be catastrophic, and modest increments in factor VIII (FVIII) activity are therapeutic. We performed transuterine i.p. gene transfer at day 15 of gestation in a murine model of hemophilia A. Normal, carrier (X(H)X), and FVIII-deficient (X(H)Y and X(H)X(H)) fetuses injected with adenoviral vectors carrying luciferase or beta-galactosidase reporter genes showed high-level gene expression with 91% fetal survival. The live-born rates of normal and FVIII-deficient animals injected in utero with adenovirus murine FVIII (3.3 x 10(5) plaque-forming units) was 87%. FVIII activity in plasma was 50.7 +/- 10.5% of normal levels at day 2 of life, 7.2 +/- 2.2% by day 15 of life, and no longer detectable at day 21 of life in hemophilic animals. Injection of higher doses of murine FVIII adenovirus at embryonic day 15 produced supranormal levels of FVIII activity in the neonatal period. PCR analysis identified viral genomes primarily in the liver, intestine, and spleen, although adenoviral DNA was detected in distal tissues when higher doses of adenovirus were administered. These studies show that transuterine i.p. injection of adenoviral vectors produces therapeutic levels of circulating FVIII throughout the neonatal period. The future development of efficient and persisting vectors that produce long-term gene expression may allow for in utero correction of genetic diseases originating in the fetal liver, hematopoietic stem cells, as well as other tissues.
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PMID:Short-term correction of factor VIII deficiency in a murine model of hemophilia A after delivery of adenovirus murine factor VIII in utero. 1055 19

Exosomes are vesicles of endocytic origin secreted spontaneously by dendritic cells (DCs). We have shown previously that exosomes can transfer antigen or MHC-peptide complexes between DCs, thus potentially amplifying the immune response. We had also identified milk fat globule EGF/factor VIII (MFG-E8), also called lactadherin, as one of the major exosomal proteins. MFG-E8 has two domains: an Arg-Gly-Asp sequence that binds integrins alphavbeta3 and alphavbeta5 (expressed by human DCs and macrophages) and a phosphatidyl-serine (PS) binding sequence through which it associates to PS-containing membranes (among which exosomes). MFG-E8 is thus a good candidate molecule to address exosomes to DCs. Here, we show that MFG-E8 is expressed by immature bone-marrow-derived DCs (BMDCs) and secreted in association with exosomes in vitro. We have generated mice expressing an inactive form of MFG-E8, fused to beta-galactosidase. Analyzing these mice, we demonstrate that MFG-E8 is expressed in vivo in splenic DCs. In a mouse DC-dependent, antigen-specific, CD4 T cell-stimulation assay, exosomes produced by MFG-E8-deficient BMDCs were barely less efficient than exosomes bearing MFG-E8. We conclude that MFG-E8 is efficiently targeted to exosomes but is not essential to address exosomes to mouse BMDCs. Involvement of MFG-E8/lactadherin in exosome targeting to other DC subpopulations, or to human DCs, is still possible.
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PMID:Accumulation of MFG-E8/lactadherin on exosomes from immature dendritic cells. 1598 8