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Sergio Salvi Mirella Trinei Luisa Lanfaloni Cynthia L. Pon 《Molecular genetics and genomics : MGG》1994,243(1):124-126
The gene encoding a 23 kDA serine esterase from the cyanobacterium Spirulina platensis has been identified, cloned, characterized and expressed in Escherichia coli. The primary structure of the esterase deduced from the DNA sequence displayed 32% sequence identity with the carboxylesterase (esterase II) encoded by estB of Pseudomonas fluorescens; the highest degree of homology is found in a stretch of 11 identical or highly conserved amino acid residues corresponding to the GXSXG consensus motif found in the catalytic site of many serine proteases, lipases and esterases. 相似文献
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During the production by mammalian cells of recombinant factor VIII from which the B domain was deleted (rFVIII), proteolytic
cleavages in the C-terminal part of the heavy chain were observed (Kjalke et al., 1995). By radioactive pulse labelling it
was investigated whether the cleavages took place inside the cells during protein synthesis or after release in the medium.
The rFVIII-producing CHO (Chinese hamster ovary) cells were cultured in the presence of 35S-methionine and then the cell lysate and the conditioned media were immunoprecipitated and analyzed by electrophoresis. By
pulse labelling and chasing for various time periods, it was shown that the cleavages only took place after secretion of the
protein from the cells. Adding cell lysate to uncleaved rFVIII caused cleavage of the heavy chain, as seen by loss of binding
to a monoclonal antibody specific for intact rFVIII, indicating that the cleavage was performed by proteinase(s) released
from the lysed cells. By incubating intact rFVIII with the multicatalytic proteinase (proteasome) present in cytoplasm and
nucleus of eukaryotic cells, loss of binding to the monoclonal antibody was observed. This indicates that the multicatalytic
proteinase, released from lysed rFVIII producing cells, could be responsible for the cleavage of rFVIII. Among several protease
inhibitors tested, only bacitracin was found to diminish the extent of cleavage. Phosphatidylserine also protected rFVIII
against cleavage, probably by binding to rFVIII.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
Giovanni Spinelli Marialuisa Melli Eva Arnold Caterina Casano Fabrizio Gianguzza Mirella Ciaccio 《Journal of molecular biology》1980,139(2):111-122
Sea urchin RNA extracted from early and mesenchyme blastula embryos and oocytes and fractionated on denaturing sucrose density gradients, was hybridized with histone DNA recombinants of Psammechinus miliaris (clone λh22) and of Paracentrotus lividus (clone pPH70). Histone sequences are found in the 9 S and larger than 9 S regions of the formamide/sucrose density gradients. The melting of the RNA-DNA duplexes obtained by hybridization of polysomal and high molecular weight RNA of embryos of P. lividus at the stage of early blastula, suggests a degree of heterogeneity in the high Mr RNA. The high Mr RNA contains at least four of the five histone gene sequences covalently linked. 相似文献
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D-amino acid oxidase (DAAO) is a flavoprotein that catalyzes stereospecifically the oxidative deamination of D-amino acids. The wild-type DAAO is mainly active on neutral D-amino acids, while basic D-amino acids are poor substrates and the acidic ones are virtually not oxidized. To present a comprehensive picture of how the active site residues can modulate the substrate specificity a number of mutants at position M213, Y223, Y238, R285, S335, and Q339 were prepared in the enzyme from the yeast Rhodotorula gracilis. All DAAO mutants have spectral properties similar to those of the wild-type enzyme and are catalytically active, thus excluding an essential role in catalysis; a lower activity on neutral and basic amino acids was observed. Interestingly, an increase in activity and (k(cat)/K(m))(app) ratio on D-aspartate was observed for all the mutants containing an additional charged residue in the active site. The active site of yeast DAAO appears to be a highly evolved scaffold built up through evolution to optimize the oxidative deamination of neutral D-amino acids without limiting its substrate specificity. It is noteworthy, that introduction of a sole, additional, positively charged residue in the active site is sufficient to optimize the reactivity on acidic D-amino acids, giving rise to kinetic properties similar to those of D-aspartate oxidase. 相似文献
6.
Pablo Ferreira das Chagas Mirella Baroni María Sol Brassesco Luiz Gonzaga Tone 《The journal of gene medicine》2020,22(1)
Musashi comprises an evolutionarily conserved family of RNA‐binding proteins (RBP) that regulate cell fate decisions during embryonic development and play key roles in the maintenance of self‐renewal and differentiation of stem cells and adult tissues. More recently, several studies have shown that any dysregulation of MSI1 and MSI2 can lead to cellular dysfunctions promoting tissue instability and tumorigenesis. Moreover, several reports have characterized many molecular interactions between members of the Musashi family with ligands and receptors of the signaling pathways responsible for controlling normal embryonic development: Notch, Transforming Growth Factor Beta (TGF‐β), Wingless (Wnt) and Hedgehog Signaling (Hh); all of which, when altered, are strongly associated with cancer onset and progression, especially in pediatric tumors. In this context, the present review aims to compile possible cross‐talks between Musashi proteins and members of the above cited molecular pathways for which dysregulation plays important roles during carcinogenesis and may be modulated by these RBP. 相似文献
7.
Roberto De Giorgio Maurizio Mazzoni Claudia Vallorani Rocco Latorre Cristiano Bombardi Maria Laura Bacci Monica Forni Mirella Falconi Catia Sternini Paolo Clavenzani 《PloS one》2016,11(2)
BackgroundThe expression of taste receptors (TASRs) and their signalling molecules in the gastrointestinal (GI) epithelial cells, including enteroendocrine cells (EECs), suggests they participate in chemosensing mechanisms influencing GI physiology via the release of endocrine messengers. TASRs mediate gustatory signalling by interacting with different transducers, including α-gustducin (Gαgust) and α-transducin (Gαtran) G protein subunits. This study tested whether Gαtran and Gαgust immunoreactive (-IR) cells are affected by a short-term (3 days) and long-term (30 days) high protein (Hp) diet in the pig GI tract.ResultIn the stomach, Gαgust and Gαtran-IR cells contained serotonin (5-HT) and ghrelin (GHR), while in the small and large intestine, Gαgust and Gαtran-IR colocalized with 5-HT-, cholecystokinin (CCK)- and peptide YY (PYY)-IR. There was a significant increase in the density of Gαtran-IR cells in the pyloric mucosa in both short- and long-term Hp diet groups (Hp3 and Hp30) vs. the control group (Ctr) (P<0.05), while the increase of Gαgust-IR cells in the pyloric mucosa was significant in Hp30 group vs. Ctr and vs. Hp3 (P<0.05); these cells included Gαtran / 5HT-IR and Gαtran / GHR-IR cells (P<0.05 and P<0.001 vs. Ctr, respectively) as well as Gαgust /5-HT-IR or Gαgust / GHR-IR cells (P<0.05 and P<0.01 vs. Ctr, respectively). In the small intestine, we recorded a significant increase in Gαtran-IR cells in the duodenal crypts and a significant increase of Gαgust-IR cells in the jejunal crypts in Hp3 group compared to HP30 (P<0.05). With regard to the number of Gαtran-Gαgust IR cells colocalized with CCK or 5-HT, there was only a significant increase of Gαtran / CCK-IR cells in Hp3 group compared to Ctr (P = 0.01).ConclusionThis study showed an upregulation of selected subpopulations of Gαgust / Gαtran-IR cells in distinct regions of the pig GI tract by short- and long-term Hp diet lending support to TASR-mediated effects in metabolic homeostasis and satiety mechanisms. 相似文献
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Ovarian steroids modulate uterine receptivity in domestic species. Luteinizing hormone (LH) stimulates prostaglandin (PG)F(2alpha) release from the porcine endometrium. However, the combined action of LH and steroids on PGs secretion has not yet been studied in pigs. The aim of the present study was to examine the effect of estradiol (E(2)) and progesterone (P(4)) on basal and LH-stimulated PGF(2alpha) and PGE(2) secretion and cyclooxygenase-2 (COX-2) protein expression in porcine endometrial stromal cells obtained on days 12-13 of the estrous cycle. Cells were cultured for 48 h in a medium containing charcoal-stripped newborn calf serum alone or supplemented with 10 nM E(2) and/or 50 nM P(4). Then, the cells were incubated for 6 h in the presence or absence of LH (20 ng/ml). Long exposure of stromal cells to steroids had no effect on PGF(2alpha) secretion, but PGE(2) release increased in the presence of E(2) plus P(4) (p<0.05). Pre-incubation of cells with E(2) plus P(4) resulted in enhanced PGF(2alpha) (p<0.05) and PGE(2) (p<0.001) secretion. Moreover, LH increased PG(2alpha) secretion in control (p<0.05) and E(2)-treated stromal cells (p<0.01). LH tended (p=0.07) to elevate PGE(2) release only in cells pre-exposed to E(2) plus P(4). The expression of COX-2 protein was increased by LH (p<0.05), but not by steroids. These results confirm the stimulatory effect of LH on PGF(2alpha) secretion and COX-2 expression in porcine stromal cells before luteolysis. PG release from porcine endometrium seems to be controlled by ovarian steroids, however only E(2)-treated-treated cells responded to LH. 相似文献