Abstract：
:pH-Dependence of hydrolytic activity of trypsin has been studied in cationic reverse micellar system of cetyltrimethylammonium bromide (CTAB) in (50% v/v) chloroform/isooctane using a positively charged substrate N(alpha)-benzoyl-L-arginine ethyl ester (BAEE). The pH of the medium was varied from 4.0 to 8.5 with addition of 0.025 M citrate-phosphate buffer containing 1 mM CaCl2. Optimum pH for maximum enzyme activity, pH(opt) in reverse micelles is found to be similar to that observed in bulk aqueous solution (8.0-8.5). However, changes in activity of trypsin (k(cat)) as a function of water content W0 (W0 = [H2O]/[CTAB]) in reverse micelles are found to be pH dependent. At low pH (4.0) and low water content (W0 = 5) the enzyme is more active in reverse micelles than in bulk aqueous solution by a factor of 2. This 'superactivity' is lost at higher W0 values and the k(cat) in reverse micelles is found to be similar to that observed in aqueous bulk. At pH 5, the enzyme activity is found to be independent of W0 while at pH 6.0-6.5 the enzyme activity is low at W0 5 and increases with water content to a constant value which is still 50% lower than that in aqueous buffer. Above pH 7, the W0-activity profile becomes distinctly bell shaped with W0 optimum around 10-15. The enzyme activity at optimum W0 is close to that observed in aqueous bulk.
journal_name
Biochimiejournal_title
Biochimieauthors
Fadnavis NW,Babu RL,Deshpande Adoi
10.1016/s0300-9084(99)80007-8subject
Has Abstractpub_date
1998-12-01 00:00:00pages
1025-30issue
12eissn
0300-9084issn
1638-6183pii
S0300908499800078journal_volume
80pub_type
杂志文章相关文献
BIOCHIMIE文献大全abstract：:The preadipocyte cell lines 3T3-L1 and 3T3-F442A are widely used to study the cellular mechanisms of preadipocyte differentiation and mature adipocyte functions. However, transfection with naked DNA is inefficient in these cell lines. Adenoviral gene transfer is a powerful technique to induce high levels of transgene ...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2005.05.010
更新日期：2005-11-01 00:00:00
abstract：:Autotaxin (ATX) is a secreted lysophospholipase D involved in synthesis of lysophosphatidic acid (LPA), a phospholipid growth factor acting via specific receptors (LPA1R to LPA6R) and involved in several pathologies including obesity. ATX is secreted by adipocytes and contributes to circulating LPA. ATX expression is ...
journal_title：Biochimie
pub_type： 杂志文章,评审
doi：10.1016/j.biochi.2013.04.010
更新日期：2014-01-01 00:00:00
abstract：:Glyoxalate is an effector of oxidative phosphorylation in isolated mitochondria : it slows down State 3 but does not affect State 4 respiration. This report presents the findings of our study on the mechanism of action of glyoxalate ; these findings are listed below. The inhibition of Stage 3 respiration by glyoxalate...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/s0300-9084(75)80145-3
更新日期：1975-01-01 00:00:00
abstract：:In parallel with crystallographic studies of ribosomes from Thermus thermophilus, a long-term program on the crystallization and structural investigations of ribosomal proteins from the same microorganism has been started at the Institute of Protein Research (Pushchino, Russia). At present, more than half of the indiv...
journal_title：Biochimie
pub_type： 杂志文章,评审
doi：10.1016/0300-9084(92)90110-z
更新日期：1992-04-01 00:00:00
abstract：:Using a new extended set of 13 amber suppressors in E coli, systematic amino-acid replacements were performed at positions 104(E) and 238(G) of TEM-1 beta-lactamase from PUC19. The enzyme is tolerant to most substitutions tested at position 104. Missense revertants E104K, E104S or E104Y exhibited only minor changes in...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/0300-9084(90)90073-p
更新日期：1990-06-01 00:00:00
abstract：:The phosphotriesterase PTE, identified in the soil bacterium Pseudomonas diminuta, is thought to have evolved in the last several decades to degrade the pesticide paraoxon with proficiency approaching the limit of substrate diffusion (k(cat)/K(M) of 4 x 10(7)M(-1)s(-1)). It belongs to the amidohydrolase superfamily, b...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2007.01.007
更新日期：2007-05-01 00:00:00
abstract：:Dyskeratosis congenita is an inherited syndrome characterised by mucocutaneous features, bone marrow failure, an increased risk of malignancy and other somatic abnormalities. There is a considerable range of clinical severity and in its occult form the disease may present as idiopathic aplastic anaemia. Genes responsi...
journal_title：Biochimie
pub_type： 杂志文章,评审
doi：10.1016/j.biochi.2007.07.017
更新日期：2008-01-01 00:00:00
abstract：:Synthesis and secretion of polysaccharides by Gram-negative bacteria are a result of a concerted action of enzymatic and channel-forming proteins localized in different compartments of the cell. The presented work comprises functional characterization of PssO protein encoded within the previously identified, chromosom...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2008.08.004
更新日期：2008-11-01 00:00:00
abstract：:Lysosomal cysteine proteinases were fractionated from partially purified rat muscle lysosomes. By gel filtration on Sephadex G75, cathepsin D was separated from two thiol-requiring proteolytic fractions of Mr 25 000 and 55 000, respectively. By chromatofocusing, the first fraction (Mr = 25 000) was resolved into three...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/0300-9084(84)90114-7
更新日期：1984-09-01 00:00:00
abstract：:The Escherichia coli protein synthesis initiation factor IF2 is a member of the large family of G-proteins. Along with translational elongation factors EF-Tu and EF-G and translational release factor RF-3, IF2 belongs to the subgroup of G-proteins that are part of the prokaryotic translational apparatus. The roles of ...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/s0300-9084(00)01200-1
更新日期：2000-12-01 00:00:00
abstract：:Kinetic parameters characterizing the catalytic activities of enzymes are typically investigated in dilute solutions. However, in reality, these reactions occur in cells that, in addition to water and ions, are full of other macromolecules including proteins, nucleic acids, lipids, and metabolites. Such a crowded envi...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2020.07.009
更新日期：2020-09-01 00:00:00
abstract：:The inhibitory action on rat liver phosphoglycerate kinase of structural analogs of the two substrates of this enzyme (beta,gamma- methyleneadenosine 5'-triphosphate for ATP and 2-phosphoglycerate for 3-phosphoglycerate) was studied. In the direction of ADP utilization, the inhibition patterns obtained with beta,gamma...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/s0300-9084(86)80201-2
更新日期：1986-04-01 00:00:00
abstract：:Although believed to be widely distributed among the animal kingdom, transforming growth factor-beta (TGF-beta) superfamily members have mainly been characterized in vertebrate and in invertebrate model organisms such as Drosophila and C. elegans. To characterize such new factors in invertebrates, a PCR screen was per...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/s0300-9084(01)01260-3
更新日期：2001-05-01 00:00:00
abstract：:The exosome is a complex of eleven subunits in yeast, involved in RNA processing and degradation. Despite the extensive in vivo functional studies of the exosome, little information is yet available on the structure of the complex and on the RNase and RNA binding activities of the individual subunits. The current mode...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2007.01.011
更新日期：2007-05-01 00:00:00
abstract：:The interactions of 6-8 ring hairpin polyamides (PAs) with the minor groove of DNA have been investigated extensively. More recent studies of large antiviral PAs (14-20 rings) active against small DNA tumor viruses lead to questions regarding the extent to which the DNA binding behaviors of the well studied, smaller P...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2019.07.021
更新日期：2019-10-01 00:00:00
abstract：:Binding of indoloquinolines with different aliphatic side chains to a parallel G-quadruplex derived from the MYC promoter sequence was characterized by optical and calorimetric measurements. ITC experiments performed at different temperatures enabled the determination of molar heat capacity changes upon quadruplex bin...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2018.11.015
更新日期：2019-02-01 00:00:00
abstract：:Human α(1)-acid glycoprotein (AGP) is a positive acute phase plasma protein containing two disulfide bridges. Structural studies have shown that under specific conditions AGP undergoes aggregation. In this study, we analysed the nature of AGP's aggregates formed under reducing and non-reducing conditions at pH 5.5 and...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2012.09.005
更新日期：2013-02-01 00:00:00
abstract：:Homocysteine (HCY) is a degradation product of the methionine pathway. The B vitamins, in particular vitamin B12 and folate, are the primary nutritional determinant of HCY levels and therefore their deficiencies result in hyperhomocysteinaemia (HHCY). Prevalence of hyperhomocysteinemia (HHCY) and related dietary defic...
journal_title：Biochimie
pub_type： 杂志文章,评审
doi：10.1016/j.biochi.2016.04.009
更新日期：2016-07-01 00:00:00
abstract：:The rate of hydrolysis of long chain triglycerides by pure bovine pancreatic lipase has been determined in the presence of variable amounts of bile salts and colipase. Cofactor-free lipase is strongly inhibited by sodium taurodesoxycholate and by mixed bovine bile salts at concentrations higher than the critical micel...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/s0300-9084(76)80572-x
更新日期：1975-01-01 00:00:00
abstract：:In order to identify conserved potential secondary structures within translational start sites, mRNA sequences derived from different species were studied with programs able to depict such features. The potential secondary structure of 71 bases around the initiator AUG or AUGs in the coding sequences of 290 eukaryotic...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/0300-9084(94)90120-1
更新日期：1994-01-01 00:00:00
abstract：:Conformational flexibility and structural fluctuations play an important role in enzyme activity. A great variety of internal motions ranging over different time scales and of different amplitudes are involved in the catalytic cycle. These different types of motions and their functional consequences are considered in ...
journal_title：Biochimie
pub_type： 杂志文章,评审
doi：10.1016/s0300-9084(98)80054-0
更新日期：1998-01-01 00:00:00
abstract：:Clustered apurinic/apyrimidinic (AP) sites are more cytotoxic than isolated AP lesions because double strand breaks (DSB) can be formed during repair of closely positioned bistranded AP sites. Formation of DSB due to simultaneous cleavage of bistranded AP sites may be regulated by proteins specifically interacting wit...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2018.04.027
更新日期：2018-07-01 00:00:00
abstract：:In the present study we have investigated the thermal stability of the globular transport protein human serum albumin (HSA), in the presence of two small chain polyethylene glycols (namely PEG 200 and PEG 400). Both near- and far-UV circular dichroism (CD) study reveal that addition of PEG moderately increases the α-h...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2014.05.009
更新日期：2014-09-01 00:00:00
abstract：:Hyper- (450 mOsm/l) and hypoosmotic exposure (150 mOsm/l) of Caco-2 cells, a human intestinal epithelial cell line, induced a twofold- and a fivefold increase in the production of IL-8, a constitutively expressed cytokine, respectively. This was observed both in the presence or in the absence of added proinflammatory ...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2004.07.009
更新日期：2004-08-01 00:00:00
abstract：:A discriminating system capable of recognizing the oxygenated sterols was investigated in human lymphocytes. After labelling entire cells with 25-hydroxy [3H] cholesterol (10 nM) the cytosol was ultracentrifuged on a linear sucrose density gradient. Bound 25-hydroxy [3H] cholesterol was located in a single peak with a...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/s0300-9084(82)80437-9
更新日期：1982-05-01 00:00:00
abstract：:In order to demonstrate the in vivo antioxidant properties of metallothioneins (MTs), the bacteria Escherichia coli was used as a cell reactor in which we compared the metal binding and antioxidative functions of MTs from different species, with different structures and polypeptide lengths. No protective effects of cy...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2007.06.005
更新日期：2007-12-01 00:00:00
abstract：:Acinetobacter baumannii encodes all enzymes required in the tricarboxylic acid (TCA) cycle and glyoxylate bypass except for isocitrate dehydrogenase kinase/phosphatase (IDHKP), which can phosphorylate isocitrate dehydrogenase (IDH) at a substrate-binding Ser site and control the carbon flux in enterobacteria, such as ...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2020.12.001
更新日期：2020-12-05 00:00:00
abstract：:We have previously shown that withdrawal of folic acid led to metabolic reprogramming and a less aggressive phenotype in a mouse cell model of triple-negative breast cancer (TNBC). Herein, we evaluate the effects of folic acid withdrawal on transcriptomic profiles in these cells. Murine cell lines were originally deri...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2020.04.005
更新日期：2020-06-01 00:00:00
abstract：:The imprinted gene Grb10 influences fetal growth, adult behavior and tumor formation. Investigating this gene often involves consecutive passaging of cells in vitro. We analyzed changes in Grb10 DNA methylation and histone modifications in serially passaged adult mouse tail-tip fibroblast cells with bisulfite genomic ...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2012.08.009
更新日期：2012-12-01 00:00:00
abstract：:TcrX/Y is one of the twelve two component system (TCS) present in Mycobacterium tuberculosis. We have investigated the TcrX/Y interaction by in silico studies, pull down assay, radioactive phosphotransfer, surface plasmon resonance as well as crosstalk analysis of TcrY with TcrA - a non-cognate response regulator. Seq...
journal_title：Biochimie
pub_type： 杂志文章
doi：10.1016/j.biochi.2009.11.009
更新日期：2010-03-01 00:00:00
