Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thin-layer radiochromatographic methods for the measurement of histaminase and histidine decarboxylase activities have been developed. The assays are specific for the respective enzymes, are sensitive and reproducible, and can be performed using commercially available substrates. The histaminase assay permits determination of enzyme activity from 2.5 mul of pregnancy sera, 1-2 X 10(6) human granulocytes, and microgram quantities of partially purified human placenta histaminase with an error of less than 5 per cent. The histidine decarboxylase assay permits measurement of nanogram quantities of newly formed histamine from as few as 2 X 10(4) rat peritoneal mast cells or rat basophilic leukemia cells with an error of less than 5 per cent.
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PMID:Histamine metabolism. I. Thin-layer radiochromatographic assays for histaminase and histidine decarboxylase enzyme activities. 0

In rat basophilic leukemia cells (2H3), a tumor analog of mast cells, the aggregation of IgE receptors results in histamine secretion and the increase in histidine decarboxylase activity which synthesizes histamine. Using inhibitors of protein kinases C, we studied the relationships between these events and protein kinase C which is activated by antigens. Histamine release is suppressed by inhibitors of protein kinase C, staurosporine, K252-a and H-7, in this decreasing order of effectiveness; and the IC50 values are 1.5 nM, 29.9 nM and 3.8 microM, respectively. The changes in the intracellular Ca concentration monitored by fura-2 fluorescence is not modified by staurosporine, although the histamine response is suppressed. Meanwhile, the increase of histidine decarboxylase was abolished by inhibitors of protein kinase C; staurosporine was the strongest, K-252a of moderate activity and H-7, the weakest, having IC50 values of 0.8 nM, 100 nM and 11.5 microM, respectively. The inhibitors of protein kinase C suppress both histamine secretion and synthesis. Therefore, the histamine synthesis may be stimulated via activation of protein kinase C to supplement the released histamine.
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PMID:Effects of inhibitors of protein kinase C on the release and synthesis of histamine in rat basophilic leukemia cells (2H3). 138 Oct

On the stimulation of rat basophilic leukemia (2H3) cells with an IgE oligomer, the intracellular Ca2+ concentration, which was measured with fura-2 as a fluorescent probe, began to increase after 1 min lag period, reached its maximum at 4 min, and gradually decreased to the original level. The histamine release occurred slightly more slowly than the increase in the intracellular Ca2+. It started 2-3 min after the stimulation, reaching a peak at 6 min and thereafter decreasing slowly. To supplement the released histamine, the activity of histidine decarboxylase, a histamine-forming enzyme, increased 5-fold several hours after the stimulation by an IgE oligomer, and this increase may be mediated by protein kinase C system.
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PMID:Release and synthesis of histamine in rat basophilic leukemia (2H3) cells. 247 45

Treatment of rat basophilic leukemia cell line (2H3) with interferon-alpha significantly increased intracellular histamine levels. On the other hand, the histidine content was decreased reciprocally by interferon in a dose-dependent manner. Concomitantly, the activity of histidine decarboxylase, the enzyme responsible for histamine synthesis, was augmented. The increase in histidine decarboxylase activity was partially abolished in co-incubation with inhibitors of ADP-ribosyltransferase, such as 3-aminobenzamide or nicotinamide. These results suggest the pivotal role of activation of histidine decarboxylase, presumably through ADP-ribosylation of the enzyme, in interferon-induced histamine synthesis.
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PMID:Induction of histidine decarboxylase in rat basophilic leukemia cells by interferon and prevention of its effect in coincubation with ADP-ribosyltransferase inhibitors. 252 50

When cells of mouse myelomonocytic leukemia cell line, WEHI-3B, were cultured in the presence of actinomycin D plus the serum which was obtained from mice injected with bacterial endotoxin, i.e., lipopolysaccharide, their histidine decarboxylase (L-histidine carboxy-lyase, EC 4.1.1.22) (HDC) activity increased about 100-fold with a peak at 48 h. According to the increase in HDC activity, the expression of surface antigens associated with macrophages, such as Mac II, Mac III and Iad, increased markedly on WEHI-3B cells as well as their morphological changes to macrophages. Histamine levels in the culture medium increased concomitantly with the increase in the HDC activity in WEHI-3B cells, whereas the histamine contents inside the cells did not increase remarkably. Furthermore, the addition of lipopolysaccharide to the culture medium caused an additional 2-fold increase in the HDC activity of WEHI-3B cells. These results indicate that the increase in HDC activity in WEHI-3B cells may represent an event in the process of the differentiation to macrophages.
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PMID:Increase of histidine decarboxylase activity in murine myelomonocytic leukemia cells (WEHI-3B) in parallel to their differentiation into macrophages. 305 14

When rat basophilic leukemia (2H3) cells were stimulated by higher oligomer, the chemically cross-linked oligomers of IgE, in the presence of calcium the activity of histidine decarboxylase (HDC, L-histidine carboxylase, E.C.4.1.1.22), a histamine-forming enzyme, was increased by 1 hr, reaching maximum activity by 2 hr, and returning to the original level by 8 hr. A similar increase in enzyme activity was observed in cells treated with phorbol myristate acetate (PMA) or oleoyl-acetylglycerol (OAG), which are known activators of protein kinase C. Removal of calcium from medium abolished the increase in HDC activity in response to higher oligomer but not that induced by PMA or OAG, suggesting that the increase in HDC activity may be mediated by protein kinase C. The increase in the HDC activity probably required induction of enzyme synthesis, because it was prevented by cycloheximide.
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PMID:Induction of histidine decarboxylase of rat basophilic leukemia (2H3) cells stimulated by higher oligomeric IgE or phorbol myristate acetate. 335 61

High levels of histidine decarboxylase activity were measured in rat basophilic leukemia cells grown in ascitic form in 4 week old WKY/N rats. The potent inhibition of this enzyme by brocresine and alpha-methylhistidine but not by alpha-methyl DOPA identified it as a specific histidine decarboxylase. Gel filtration and polyacrylamide gel electrophoresis revealed a molecular weight of 125,000 for the native enzyme, similar to that of fetal rat liver histidine decarboxylase. Using rat basophilic leukemia cells as starting material, histidine decarboxylase was purified extensively in a seven step procedure. Electrophoresis under denaturing conditions revealed that histidine decarboxylase is a dimeric protein consisting of two identical subunits with a molecular weight of 62,000. The results indicate that rat basophilic leukemia cells provide a new and rich source for the purification of histidine decarboxylase.
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PMID:Histidine decarboxylase: isolation and molecular characteristics. 650 33

Two species of L-histidine decarboxylase (HDC) mRNA were found in the KU-812-F basophilic cell line, but only the 2.4-kilobase (kb) one encodes the functional HDC (Mamune-Sato, R., Yamauchi, K., Tanno, Y., Ohkawara, Y., Ohtsu, H., Katayose, D., Maeyama, K., Watanabe, T., Shibahara, S., and Takishima, T. (1992) Eur. J. Biochem. 209, 533-539). The 3.4-kb one encodes a truncated HDC protein and is also found in human leukemia-derived cell lines HEL and KCL-22. To clarify the mechanisms that regulate transcription of the HDC gene and generate the two species of mRNA, we have isolated genomic DNA clones coding for the HDC from human genomic libraries. Structural analysis of the isolated clones revealed that the human HDC gene is composed of 12 exons spanning approximately 24 kb. Genomic DNA blot analysis suggested that HDC is encoded by a single copy gene. The structural analysis also demonstrated that the heterogeneity of the HDC mRNA is caused by an insertion of the seventh intron sequence and alternative use of the splicing acceptor site at the 12th exon. The transcription start site of the HDC gene and the nucleotide sequences of the promoter and first exon regions were determined. We found a TATA-like sequence, a GC box, four CACC boxes, four GATA consensus sequences, and six leader-binding protein-1 binding motifs in the promoter region of the HDC gene.
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PMID:Structure of the L-histidine decarboxylase gene. 828 22

We have expressed and characterized human recombinant 74-kDa (rHDC74) and 54-kDa (rHDC54) L-histidine decarboxylases (HDCs) in Sf9 cells. By immunoblot analysis, rHDC74 and rHDC54 were shown to be localized predominantly in the particulate and soluble fractions, respectively. rHDC74 exhibited histamine-synthesizing activity equivalent to that of rHDC54. The existence of 74- and 54-kDa HDCs was also confirmed in the particulate and supernatant fractions of the cell lysate, respectively, from the human basophilic leukemia cell line KU-812-F. The ratio of HDC activity to immunoreactivity was similar for the two forms of the enzyme. The specific activity of purified rHDC54 (1.12 mumol/mg/min) was comparable to those of HDCs from other mammalian tissues or cells. The purified rHDC54 was eluted as a monomer form from a Superdex-200 column; the molecular mass of the enzyme was approximately 54 kDa on SDS-polyacrylamide gel electrophoresis without 2-mercaptoethanol. The HDC activity of rHDC54 significantly decreased on dialysis against buffer without pyridoxal 5'-phosphate; addition of pyridoxal 5'-phosphate to the dialysate readily increased in the enzyme activity to the original activity. Taken together, these results suggest that human HDC functions as both 74- and 54-kDa forms having equivalent HDC activity, which are localized in the particulate and soluble fractions, respectively, and that the latter form exhibits its activity as a monomer form.
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PMID:Comparative studies of human recombinant 74- and 54-kDa L-histidine decarboxylases. 853 May 24

Effects of carbachol and antigen (dinitrophenylated bovine serum albumin) on histamine release and histidine decarboxylase (HDC, the enzyme synthesizing histamine) activity were studied in 2H3-m1 cells, a subclone of rat basophilic leukemia cells that expresses human muscarinic m1 receptors through transfection with the gene. Carbachol stimulated the release of histamine and the activity of HDC with 30-50% the intensity of the maximal effect of the antigen. Pirenzepine, an m1 antagonist, inhibited these carbachol effects in a dose-dependent manner. The effect of the combination of carbachol and antigen on histamine release showed no additivity. These results indicate that these effects of carbachol are exerted via m1 receptors, and they suggest that the actions of carbachol and antigen on histamine release share a common pathway(s), and the release and synthesis of histamine have a positive relationship like in a feedback system.
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PMID:The release and subsequent synthesis of histamine in a transfected subclone of rat basophilic leukemia cells that expresses human muscarinic m1 receptors. 856 54


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