Abstract:
:We have purified and characterized the Ascaris suum gamma-glutamylcysteine synthetase, the rate-limiting step in the glutathione biosynthesis. The purified enzyme exhibited a specific activity of 18 U (mg protein)-1. Estimation of the molecular mass of the native enzyme by FPLC on Superdex S-200 revealed the presence of two enzyme activity peaks corresponding to molecular masses of 100 and 70 kDa. The higher-molecular-mass component could be dissociated by repeated gel filtration into the 70-kDa protein which is the enzymatically active subunit. The apparent Km values of the A. suum enzyme for L-aminobutyrate, L-cysteine and L-glutamate were 0.31, 0.41 and 0.94 mM, respectively. D,L-Buthionine-S,R-sulfoximine and cystamine showed time-dependent irreversible inhibitory effects on the A. suum enzyme activity with Ki values of 0.05 and 1.11 microM, respectively. The Ki values for the corresponding enzyme from rat kidney with D,L-buthionine-S,R-sulfoximine and cystamine were 7.19 and 22.2 microM, respectively. The time of half-inactivation of the enzyme at infinite concentration of D,L-buthionine-S,R-sulfoximine, tau 50, was determined to be 3.1 and 1.34 min, for the parasite and mammalian enzymes respectively. For cystamine, a tau 50 value of 3.32 min for the A. suum gamma-glutamylcysteine synthetase was determined, while a value of 2 min in case of rat kidney enzyme was found. The A. suum enzyme activity was competitively inhibited by glutathione with a Ki value of 0.11 mM.(ABSTRACT TRUNCATED AT 250 WORDS)
journal_name
Mol Biochem Parasitoljournal_title
Molecular and biochemical parasitologyauthors
Hussein AS,Walter RDdoi
10.1016/0166-6851(94)00064-tsubject
Has Abstractpub_date
1995-06-01 00:00:00pages
57-64issue
1-2eissn
0166-6851issn
1872-9428pii
0166-6851(94)00064-Tjournal_volume
72pub_type
杂志文章abstract::Leishmania parasites cycle between the alimentary tract of a sandfly vector as free-living promastigotes and the acidified phagolysosomes of the vertebrate host macrophage as aflagellated amastigotes. The differentiation process can be mimicked in host-free culture by switching promastigotes (e.g. 25 degrees C, neutra...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/j.molbiopara.2008.12.012
更新日期:2009-05-01 00:00:00
abstract::Surface proteins of male and female gametes of Plasmodium gallinaceum were radioiodinated by the lactoperoxidase method, immunoprecipitated with stage specific antisera and separated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Stage specificity of the surface antigens was further studied by competiti...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(84)90061-6
更新日期:1984-04-01 00:00:00
abstract::The precursor of the glycosylphosphatidylinositol membrane anchor of the variant surface glycoprotein of Trypanosoma brucei is known as glycolipid A and it has the structure: EtN-PO4-6Man alpha 1-2Man alpha 1-6Man alpha 1-4GlcN alpha 1-6myo-inositol-PO4-(sn-1,2-dimyristoylglycerol). This precursor exists in equilibriu...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(96)02585-6
更新日期:1996-05-01 00:00:00
abstract::Cyclic AMP-dependent protein kinase (protein kinase A, PKA) is a key element in many cell signaling pathways. An essential role of Plasmodium falciparum PKA (PfPKA) activity was reported in the intraerythrocytic growth of the malaria parasite. However, molecular characterization of PfPKA using purified recombinant pro...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/j.molbiopara.2008.03.011
更新日期:2008-08-01 00:00:00
abstract::Erythrocyte invasion by malaria parasites is a multi-step process requiring specific molecular interactions between merozoites and erythrocyte surface receptors. Human Duffy blood group protein is the receptor for Plasmodium vivax merozoite invasion to red blood cells. The cognate parasite ligand for Duffy protein is ...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/j.molbiopara.2005.11.005
更新日期:2006-04-01 00:00:00
abstract::In trypanosomes and related kinetoplastida a common short 5' leader sequence is encoded by the highly repetitive mini-exon gene and added to all protein coding mRNAs by trans-splicing. To initiate a search for transcription factors associated with transcription of the mini-exon we have used an electrophoretic mobility...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(88)90136-3
更新日期:1988-07-01 00:00:00
abstract::The technique of RNA interference (RNAi) is exceedingly useful for knocking down the expression of a specific mRNA in African trypanosomes and other organisms for the purpose of examining the function of its gene. However, when we attempted to apply RNAi in the Latin American trypanosome, Trypanosoma cruzi, to diminis...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/j.molbiopara.2003.10.005
更新日期:2004-02-01 00:00:00
abstract::A wide range of secondary biological functions have been documented for eukaryotic aminoacyl-tRNA synthetases including roles in transcriptional regulation, mitochondrial RNA splicing, cell growth, and chemokine-like activities. The asparaginyl-tRNA synthetase (AsnRS) of the filarial nematode, Brugia malayi, is a high...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/j.molbiopara.2012.06.003
更新日期:2012-09-01 00:00:00
abstract::Following the demonstration that the transport of melaminophenyl arsenical drugs in Trypanosoma brucei is dependent upon an unusual adenosine nucleoside transporter (Carter and Fairlamb, Nature 361 (1993) 173-175) we have investigated adenosine transport in the related parasite Trypanosoma equiperdum (Botat1.1) and a ...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(95)00120-p
更新日期:1995-07-01 00:00:00
abstract::Clones of the rRNA genes of Ostertagia ostertagi were selected from a library prepared from the genomic DNA of adult worms of strain LA-2. A 13.4-kb insert in a clone, lambda OOR78, is comprised of one complete 7.5-kb rDNA unit and portions of two adjacent units. The rDNA unit is directly repeated in a head-to-tail fa...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(91)90095-n
更新日期:1991-04-01 00:00:00
abstract::A restriction fragment from a cloned kinetoplast minicircle DNA has been shown to be diagnostic for Leishmania major. This 402-bp TaqI fragment has been used routinely (as a radiolabelled probe) to detect 10(4) parasites in simple dot blots, both experimentally and in epidemiological surveys. It positively identified ...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(89)90153-9
更新日期:1989-12-01 00:00:00
abstract::A Plasmodium falciparum gene closely linked to the chloroquine resistance locus encodes PfCG2, a predicted 320-330kDa protein. In the parasitized erythrocyte, PfCG2 expression rises sharply in the trophozoite stage and is detected in electron-dense patches along the parasitophorous vacuolar membrane (PVM), in the cyto...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/j.molbiopara.2005.07.009
更新日期:2005-12-01 00:00:00
abstract::We have examined changes in the relative synthesis of individual proteins in promastigotes of Leishmania major subjected to decreasing serum levels in vitro. We observed increases in the relative synthesis of the putative heat-shock proteins of 82 and 70 kDa and of proteins of 79 and 41 kDa but decreases in the synthe...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(89)90136-9
更新日期:1989-06-01 00:00:00
abstract::Tubulin-binding cofactor C stimulates GTPase activity and contributes to the release of the heterodimeric α/β-tubulin from a super-complex of tubulin monomers and two ancillary cofactors. We have determined the 2.2 Å resolution crystal structure of the C-terminal domain of tubulin-binding cofactor C from Leishmania ma...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/j.molbiopara.2015.05.003
更新日期:2015-05-01 00:00:00
abstract::The complex life cycles of many protozoan parasites require the ability to respond to environmental and developmental cues through regulated gene expression. Traditionally, parasitologists have investigated these mechanisms by identifying and characterizing proteins that are necessary for the regulated expression of t...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章,评审
doi:10.1016/j.molbiopara.2007.10.004
更新日期:2008-02-01 00:00:00
abstract::The livers of chickens maintained on a diet containing an effective in vivo level (70 ppm) of arprinocid, an anticoccidial agent, were found to contain 0.64 ppm of this drug and 0.33 ppm of a metabolite, arprinocid-1-N-oxide. When arprinocid was tested against Eimeria tenella in cultures of chick kidney epithelial cel...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(80)90051-1
更新日期:1980-10-01 00:00:00
abstract::The ADP ribosylation factors (Arfs) are a highly conserved subfamily of the Ras small GTPases with crucial roles in vesicle budding and membrane trafficking. Unlike in other eukaryotes, the orthologue of Arf1 in the host bloodstream form of Trypanosoma brucei is essential for the maintenance of endocytosis. In contras...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/j.molbiopara.2007.06.009
更新日期:2007-10-01 00:00:00
abstract::gamma-Glutamyl transpeptidase, which is of central importance in the degradation of glutathione, was purified from Ascaris suum to apparent homogeneity. The enzyme was found to be a predominantly membrane-bound protein and was solubilized by Triton X-100. The purified enzyme, which exhibits a specific activity of 1009...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(96)02573-x
更新日期:1996-04-01 00:00:00
abstract::The phylum Nematoda comprises a diverse group of roundworms that includes parasites of vertebrates, invertebrates, and plants. Human-parasitic nematodes infect more than one billion people worldwide and cause some of the most common neglected tropical diseases, particularly in low-resource countries [1]. Parasitic nem...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章,评审
doi:10.1016/j.molbiopara.2016.05.007
更新日期:2016-07-01 00:00:00
abstract::The influence of pH on the activity of purified pyruvate kinase (ATP:pyruvate 2-O-phosphotransferase, EC 2.7.1.40) from Trypanosoma brucei has been studied. The Km for the coenzyme ADP is pH-dependent and shows the involvement of a dissociable group on the free enzyme with a pKa of 6.5-6.7. The cooperative interaction...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(81)90032-3
更新日期:1981-11-01 00:00:00
abstract::Protozoan parasites of the genus Leishmania have a digenetic lifecycle, alternating between the promastigote and amastigote stages. The extracellular promastigote resides within a sandfly vector, while the obligate intracellular amastigote stage replicates in the phagolysosome of mammalian host macrophages. Adaptation...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/j.molbiopara.2007.02.010
更新日期:2007-06-01 00:00:00
abstract::The major proteolytic activity of Trypanosoma cruzi is a cathepsin L-like cysteine protease expressed in all stages of the parasite. As an initial step in identifying possible functions of this enzyme in the life cycle of T. cruzi, and examining its potential as a target for rational drug design, two fluoromethyl keto...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(93)90086-d
更新日期:1993-03-01 00:00:00
abstract::The (Ca(2+)-Mg2+)ATPase activity in microsomes of Schistosoma mansoni is fully inhibited by vanadate (I50 = 2.5 microM). 45Ca2+ is accumulated within microsomal vesicles in an ATP-dependent process that is enhanced 5-fold in the presence of 40 mM phosphate. Accumulated 45Ca2+ is rapidly released by 5 microM of the Ca2...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(92)90049-p
更新日期:1992-06-01 00:00:00
abstract::The binding of tritiated benzimidazoles (BZs)-albendazole, parbendazole, oxibendazole, mebendazole, oxfendazole and fenbendazole-to crude tubulin extracts from BZ-susceptible and -resistant Haemonchus contortus has been examined. For all BZs, the binding was substantially lower in the resistant isolate. The extent of ...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(86)90122-2
更新日期:1986-05-01 00:00:00
abstract::The karyotype and chromosomes of the human malaria parasite Plasmodium falciparum have been well characterized in recent years. Here we present karyotype maps of the three other human malaria species, P. vivax, P. malariae and P. ovale. Chromosomes of these species were found to be of significantly higher molecular we...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/s0166-6851(99)00045-6
更新日期:1999-06-25 00:00:00
abstract::The extent of structural conservation of the Plasmodium falciparum sporozoite surface protein gene, STARP, recently characterized in the T9/96 clone, has been analyzed using the polymerase chain reaction. Results from Ivory Coast and Thai clones, field isolates originating from Brazil and Kenya and laboratory-maintain...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(94)00138-3
更新日期:1994-10-01 00:00:00
abstract::Two dimensional electrophoresis has been used to examine protein variation in clones of two Plasmodium falciparum isolates. Variant forms of 12 proteins were detected. Five genetically distinct parasite types were identified in one isolate, and two in the second isolate. Examination of uncloned parasites using this te...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(85)90085-4
更新日期:1985-08-01 00:00:00
abstract::Nucleotide-sugar transporters (NSTs) transport activated sugars (e.g. UDP-GlcNAc) from the cytosol to the lumen of the endoplasmic reticulum or Golgi apparatus where they are used to make glycoproteins and glycolipids. UDP-Glc is an important component of the N-glycan-dependent quality control (QC) system for protein ...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/j.molbiopara.2008.01.004
更新日期:2008-05-01 00:00:00
abstract::Antigenic switching in Trypanosoma brucei can occur either by the production of a telomeric copy of a variant surface glycoprotein (VSG) gene through a gene conversion mechanism or by the nonduplicative activation of a telomeric VSG gene. The 5 VSG gene telomeric copy that is expressed in IsTaR 1 variant antigenic typ...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(85)90045-3
更新日期:1985-06-01 00:00:00
abstract::Trypanosoma brucei is a unicellular parasite that is transmitted from one mammalian host to the next by tsetse flies. The expression of many trypanosome genes is regulated during the life cycle but there is no evidence for developmental control of transcription by RNA polymerase II. T. brucei expresses at least two he...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(95)02503-0
更新日期:1995-12-01 00:00:00