Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.5.1.4 (deaminase)
5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Palytoxin (PTX), one of the most toxic nonprotein molecules known, is cytotoxic at picomolar concentrations against a wide variety of cell types. In contrast to most cytotoxins, PTX exerts its activity extracellularly. A method for targeting PTX to tumor cells is described in which a monoclonal antibody-enzyme conjugate activates a PTX prodrug at surfaces of tumor cells. The prodrug, N-(4'-hydroxyphenylacetyl)palytoxin (NHPAP), was prepared by reacting PTX with an active ester of 4-hydroxyphenylacetic acid. NHPAP was 1000 times less toxic than PTX to a panel of carcinoma and lymphoma cell lines. The cytotoxic activity of the combination of penicillin G amidase from Escherichia coli with NHPAP was equal to PTX. Two cell lines that were multidrug resistant showed no enhanced resistance to NHPAP +/- penicillin G amidase. Immunologically specific activation of NHPAP took place when H2981 cells (L6 antigen positive) were treated with the monoclonal antibody conjugate L6-penicillin G amidase followed by NHPAP. This system is distinguished from other prodrug activation schemes, since the released drug exerts its activity extracellularly, has high potency, and may be able to overcome the multidrug resistant phenotype.
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PMID:N-(4'-hydroxyphenylacetyl)palytoxin: a palytoxin prodrug that can be activated by a monoclonal antibody-penicillin G amidase conjugate. 135 20

The two monoclonal antibodies (mAb), L6 (anti-carcinoma), and 1F5 [anti-(B-cell-lymphoma)], were chemically linked to the enzyme penicillin-V amidase (PVA), which hydrolyzes phenoxyacetamides, to explore the potential of using mAb-enzyme conjugates for the localization of chemotherapeutic drugs at tumor cells. The phenoxyacetamide derivatives of doxorubicin and melphalan were prepared, yielding the less toxic amides, doxorubicin-N-p-hydroxyphenoxyacetamide (DPO) and melphalan-N-p-hydroxyphenoxyacetamide (MelPO). These were hydrolyzed by PVA to doxorubicin and melphalan respectively. In vitro studies with the L6-positive lung carcinoma cell line, H2981, and the 1F5-positive B-cell lymphoma line, Daudi, showed that DPO was 80-fold less toxic to H2981 cells and 20-fold less toxic to Daudi cells than doxorubicin, and its toxicity was substantially increased when the H2981 cells were pretreated with L6-PVA or the Daudi cells were pretreated with 1F5-PVA. The cytotoxic effect was antigen-specific, since only the binding mAb-enzyme conjugate increased the cytotoxicity of the prodrug. MelPO was more than 1000-fold less toxic than melphalan to H2981 cells and more than 100-fold less toxic than melphalan to Daudi cells. Pretreatment with the mAb-PVA conjugates did not enhance the toxicity of MelPO in either cell line, because PVA hydrolyzes the phenoxyacetamide bond of MelPO too slowly to generate a toxic level of melphalan.
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PMID:Antibody-penicillin-V-amidase conjugates kill antigen-positive tumor cells when combined with doxorubicin phenoxyacetamide. 211 31

The activity of cobalt-activated acylase was determined in the serum of mice with transplantable leukemia (P 388, L 1210 standard, L 1210/ara-C, L 1210/CH3-G, plasmocytoma ADJPC-5, lymphoma AKSL-4 and natural leukemia in mice NZB). A statistically significant increase in enzyme activity in all leukemias except lymphatic leukemia has been demonstrated. The results suggest possibility of using the enzymatic measurement as a marker of transplantable leukemia in mice.
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PMID:Serum cobalt-activated acylase as a marker of transplantable leukemia in mice. 327 96

Three new fluoroarabinosylpyrimidine nucleosides (FIAC, FIAU and FMAU) were tested for in vitro activity against oncogenic and nononcogenic strains of Marek's disease virus (MDV) and herpesvirus of turkeys (HVT). Marek's disease is a herpesvirus-induced lymphoma in chickens. Nononcogenic strains of MDV and HVT can protect against this disease. All viruses were inhibited by 1 microM of these drugs in chick kidney cell (CKC) cultures, but only FMAU and FIAU were active in chicken embryo fibroblast (CEF) and spleen cell cultures. It was determined that whereas CKC produced the enzyme 2'-deoxycytidine-deaminase which is needed to deaminate FIAC to FIAU, CEF were devoid of this enzyme activity. In addition, the deaminase inhibitor 3,4,5,6-tetrahydrouridine prevented the antiviral activity of FIAC in CKC. FMAU was not active against two Marek's disease-derived lymphoblastoid tumor cell lines.
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PMID:Cell-specific antiviral activity of 1-(2-fluoro-2-deoxy-beta-D-arabinofuranosyl)-5-iodocytosine (FIAC) against Marek's disease herpesvirus and turkey herpesvirus. 609 79

2-Chlorodeoxyadenosine (CdA), an adenosine-deaminase-resistant purine deoxynucleoside, is markedly toxic toward human T-lymphoblastoid cell lines in vitro and is an effective agent against L1210 leukemia in vivo. The present studies have examined the toxicity, and in some cases, metabolism, of CdA in (1) multiple established human cell lines of varying phenotype, (2) leukemia and lymphoma cells taken directly from patients, (3) normal bone marrow cells, and (4) normal peripheral blood lymphocytes. Nanomolar concentrations of CdA blocked the proliferation of lymphoblastoid cell lines with a high ratio of deoxycytidine kinase to deoxynucleotidase. The drug had virtually no effect on the growth of cell lines derived from solid tissues. The CdA inhibited the spontaneous uptake of tritiated thymidine by many T and non-T, non-B acute lymphoblastic leukemia cell specimens at concentrations less than or equal to 5 nM. The same concentrations did not impair either thymidine uptake or granulocyte-monocyte colony formation by normal bone marrow cells. In common with deoxyadenosine, but unlike several other agents affecting purine and purine metabolism, CdA was lethal to resting normal T lymphocytes and to slowly dividing malignant T cells. In both resting and proliferating lymphocytes, the CdA was phosphorylated by deoxycytidine kinase and entered a rapidly turning over nucleotide pool. Dividing lymphocytes also incorporated abundant CdA into DNA. The selective toxicity of CdA toward both dividing and resting lymphocytes may render the drug useful as an immunosuppressive or antileukemic agent.
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PMID:Specific toxicity of 2-chlorodeoxyadenosine toward resting and proliferating human lymphocytes. 613 5

The size of the dCTP pool has been implicated as a possible regulator of DNA synthesis. In this investigation we correlate large intracellular variations in deoxyribonucleoside triphosphate levels to the growth rates and cell-cycle kinetics of mouse S49 T-lymphoma cells. Wild-type and a mutant line AzidoC-100-5, lacking dCMP-deaminase activity resulting in a 10-fold expanded dCTP pool were studied and compared using flow cytometry, centrifugal elutriation and nucleoside triphosphate determinations. An increase in the dCTP pool was closely correlated to the passage of cells from G1 to S phase in both cell types. Addition of thymidine to wild-type and mutant cells resulted in an accumulation of cells in early S phase, concomitant with a decreased dCTP level. Mutant cells excreted large amounts of deoxycytidine into the medium which partially protected the cells from thymidine inhibition. The doubling times for the mutant and wild-type cells were very similar but the mutant had a somewhat prolonged S phase and shortened G1 phase compared with the wild-type cells. Large changes in the DNA precursor levels were produced by addition of thymidine to mutant cultures. This gave no change in the growth rate but a somewhat shortened S phase and prolonged G1. The biochemical background for these effects is discussed.
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PMID:Deoxyribonucleoside triphosphate metabolism and the mammalian cell cycle. Effects of thymidine on wild-type and dCMP deaminase-deficient mouse S49 T-lymphoma cells. 648 55

The adenosine-deaminase (ADA) activity was evaluated in CSF samples from 263 patients with AIDS. An elevated ADA activity in CSF was found in patients with: antibodies to toxoplasmosis, syphilis or cytomegalovirus; Cryptococcus neoformans or their antigens; tuberculous meningitis; lymphoma. There was no statistical difference among all these groups in respect to ADA activity. However, the ADA activity in CSF from AIDS patients without CSF changes other than HIV antibodies, even unspecific changes, was not elevated. This may suggest that ADA is related to AIDS associated pathologies activity rather than to HIV infection itself.
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PMID:[Adenosine deaminase in the cerebrospinal fluid of patients with acquired immunodeficiency syndrome]. 872 68

We have identified a novel gene referred to as activation-induced deaminase (AID) by subtraction of cDNAs derived from switch-induced and uninduced murine B lymphoma CH12F3-2 cells, more than 80% of which switch exclusively to IgA upon stimulation. The amino acid sequence encoded by AID cDNA is homologous to that of apolipoprotein B (apoB) mRNA-editing enzyme, catalytic polypeptide 1 (APOBEC-1), a type of cytidine deaminase that constitutes a catalytic subunit for the apoB mRNA-editing complex. In vitro experiments using a glutathione S-transferase AID fusion protein revealed significant cytidine deaminase activity that is blocked by tetrahydrouridine and by zinc chelation. However, AID alone did neither demonstrate activity in C to U editing of apoB mRNA nor bind to AU-rich RNA targets. AID mRNA expression is induced in splenic B cells that were activated in vitro or by immunizations with sheep red blood cells. In situ hybridization of immunized spleen sections revealed the restricted expression of AID mRNA in developing germinal centers in which modulation of immunoglobulin gene information through somatic hypermutation and class switch recombination takes place. Taken together, these findings suggest that AID is a new member of the RNA-editing deaminase family and may play a role in genetic events in the germinal center B cell.
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PMID:Specific expression of activation-induced cytidine deaminase (AID), a novel member of the RNA-editing deaminase family in germinal center B cells. 1037 55

Periodically the World Health Organization and currently the International Union of Immunology Societies publish a classification of primary immunodeficiency diseases (PID) that includes diagnostic and therapeutic guidelines. The latest of these publications dates from 1999 and includes a new group of PID, the proliferative autoimmune syndromes. Furthermore, new forms of severe combined immunodeficiency (SCID) and of recessive autosomal agammaglobulinemia are described. From the publication of this classification until the end of the year 2000 a minimum of three new PIDs have been described and a further two should probably be added. Progress in the molecular biology of these diseases has given rise not only to more accurate diagnosis but also to greater insight into the clinical spectrum of these diseases. A mutation or deletion in a gene can provoke the complete absence of its product; sometimes expression is partial or normal but functional activity is absent or defective. In certain cases, partial or defective activity causes variant forms of the disease presenting symptomatology or atypical cellular phenotype. In other cases, this is not cause of the variant form, which can appear in interfamilial cases sharing the same mutation. In these cases, these differences can be attributed to environmental factors or to other genes able to modify the affected gene. In this article we provide examples of variant forms in several PIDs. Some are late onset forms, such as X-linked agammaglobulinemias diagnosed in adults, since until diagnosis, clinical symptomatology was minimal. In adenosine-deaminase deficiency, a serious and highly lymphoproliferative form of SCID, patients have been described whose symptomatology began after the age of 20 years. Another SCID, RAG1 and RAG2 recombinase deficiency, may produce a typical form with a characteristic T-B-NK + phenotype, Omenn's syndrome, or forms with an unexpected T-B + NK + phenotype. Deficiency in common gamma chain receptor for IL-2 may produce phenotypical variants that can lead to diagnostic error. X-linked lymphoproliferative syndrome may present as fulminant infectious mononucleosis, as leukemia or lymphoma or as hipo- or agammaglobulinemia. Possibly, some patients diagnosed with common variable immunodeficiency or with x-linked agammaglobulinemia do in fact have this syndrome. Chronic granulomatous disease is usually of early-onset, but late-onset forms have been described. In one case the first clinical manifestation was produced when the patient was 60 years old. The above examples serve to highlight that, even though PIDs are usually suspected by pediatricians, in some cases the diagnosis may be missed by internists or non-pediatricians. Moreover, the clinical and laboratory findings of these variant forms must be determined to carry out an early diagnosis, which is essential for a favorable therapeutic outcome.
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PMID:[Primary immunodeficiencies. Clinical features and variant forms]. 1143 82

Cell shrinkage and loss of cell viability by apoptosis have been examined in cultured CD95(Fas/Apo-1)-expressing leukemia-derived CEM and HL-60 cells subjected to acute deprivation of glutamine, a major compatible osmolyte engaged in cell volume control. Glutamine deprivation-mediated cell shrinkage promoted a ligand-independent activation of the CD95-mediated apoptotic pathway. Cell transfection with plasmids expressing FADD-DN or v-Flip viral proteins pointed to a functional clustering of CD95 receptors at the cell surface with activation of the 'extrinsic pathway' caspase cascade. Accordingly, cell shrinkage did not induce apoptosis in CD95 receptor-negative lymphoma L1210 cells. Replacement of glutamine with surrogate compatible osmolytes counteracted cell volume decrement and protected the CD95-expressing cells from apoptosis. A glutamine deprivation-dependent cell shrinkage with activation of the CD95-mediated pathway was also observed when asparaginase was added to the medium. Asparagine depletion had no role in this process. The cell-size shrinkage-dependent apoptosis induced by glutamine restriction in CD95-expressing leukemic cells may therefore be of clinical relevance in amidohydrolase enzyme therapies.
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PMID:Glutamine deprivation-mediated cell shrinkage induces ligand-independent CD95 receptor signaling and apoptosis. 1159 98


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