Search results for "PMSF"
showing 8 items of 8 documents
Influence of ATPase activity on PPi dependent H+-transport in tonoplast vesicles of Acer pseudoplatanus
1994
Abstract Tonoplast H + -ATPase and H + -pyrophosphatase (H + -PPase) were previously characterized in Acer pseudoplatanus cells (A. Pugin et al., Plant Sci., 73 (1991) 23–34; A. Fraichard et al., Plant Physiol. Biochem., 31 (1993) 349–359). The present study concerns the relationships between these two enzymes in vitro. ATP and PPi hydrolysis were additive and the inhibition of one did not affect the activity of the second one. ATP and PPi H + -transports were also additive. The H + -PPase inhibition did not change ATP-dependent H + -transport but H + -ATPase inhibition inhibited the PPi dependent H + -transport. Because H + -PPase was reported to transport H + and K + into the vacuole (Dav…
Cytokinin affects nitrate reductase expression through the modulation of polyadenylation of the nitrate reductase mRNA transcript
1993
Abstract Cytokinin (CK) and low-intensity light effects in modulating nitrate reductase (NR) activity, NR protein and NR encoding mRNAs were studied in tobacco cell suspension cultures. NR activity was strikingly enhanced by CK in dark- as well as in light-grown cells whereas it was less affected by light alone. NR protein accumulation was stimulated by the hormone in the light only; then a CK light-dependent regulation of NR activity was suggested. Light enhanced the steady-state levels of hybridisable total NR mRNA and a light-inductive effect was also observed after transfer from dark to light; this effect was dependent on sucrose supply and was enhanced in CK-supplied cells. NR poly(A) …
Cadmium binding proteins induced in exposed freshwater crayfish Procambarus clarkii.
1989
This work describes results on the characterization of cadmium binding proteins (Cd-BPs) obtained from cadmium exposed freshwater crayfish Procambarus clarkii. After acclimation to laboratory conditions, induction of Cd-BPs was achieved by water exposure at a concentration of 100 micrograms Cd/L during 2, 15, and 30 d. In accordance with the method followed by Engel and Brouwer, in each case two midgut glands were minced and homogenized in Tris-HC1 buffer with PMSF to prevent protease activity and DTT to maintain reducing conditions. The homogenate was centrifuged, heat treated, applied to a column of Sephadex G-75, and eluted with the same buffer (pH 8.6). Absorbances of the fractions coll…
Putative high mobility group non-histone chromosomal proteins from pea (Pisum sativum)
1991
Abstract Three putative HMG proteins, 1P, 2P and 3P have been isolated from pea ( Pisum sativum L. cv. Lincoln) nuclei by extraction with either 5% perchloric acid or 0.35 M NaCl and purified by preparative electrophoresis. The amino acid analysis showed many of the typical features of the HMG proteins, although 1P and 2P possess a somewhat reduced content of acidic amino acids and 3P has less than 20% basic amino acids. Peptide mapping with Staphylococcus aureus V8 protease suggested that none of the proteins are proteolytic products of histone H1.
Rev protein suppression of complex formation between nuclear proteins and rev-responsive element-containing RNA of human immunodeficiency virus-1
1995
The Rev protein from human immunodeficiency virus type 1 (HIV-1) is known to bind Rev responsive element (RRE) sequence of HIV-1 mRNA. This interaction is thought to enhance expression of viral structural proteins but the mechanism for this effect is uncertain. The aim of this study was to investigate (i) whether other cellular proteins also bind to the RRE sequence and (ii) whether binding of cellular proteins to RRE RNA is influenced by Rev protein. Our results revealed that a variety of RNA-protein complexes are formed when in vitro transcribed RRE-containing RNA is incubated with proteins present in HeLa nuclear extracts. The molecular masses of the most prominent bands in RNase protect…
Creatine kinase is the main target of reactive oxygen species in cardiac myofibrils.
1996
Abstract Reactive oxygen species (ROS) have been reported to alter cardiac myofibrillar function as well as myofibrillar enzymes such as myosin ATPase and creatine kinase (CK). To understand their precise mode and site of action in myofibrils, the effects of the xanthine/xanthine oxidase (X/XO) system or of hydrogen peroxide (H 2 O 2 ) have been studied in the presence and in the absence of phosphocreatine (PCr) in Triton X-100–treated cardiac fibers. We found that xanthine oxidase (XO), with or without xanthine, induced a decrease in maximal Ca 2+ -activated tension. We attributed this effect to the high contaminating proteolytic activity in commercial XO preparations, since it could be p…
Complement Receptor Analogous Factors in Human Serum: I. Isolation of a Molecule Inhibitory for Complement Dependent Rosette Formation, its Identific…
1979
Abstract A glycoprotein was isolated from human plasma which partially inhibited C3 carrying erythrocytes from binding to complement receptor cells (CR + C). Based on its physicochemical characteristics and its antigenicity this glycoprotein was identified as aI-antitrypsin (α 1 -AT). The activity of α 1 -AT towards-C3 and its fragments was unaffected by heating but it was destroyed by periodic acid. The isolated carbohydrate moiety of α 1 -AT showed the same effect as the intact molecule. Using F(ab) 2 of IgG-anti-α 1 -AT, α 1 -AT could be demonstrated on Raji cells and human erythrocytes. Treatment of these CR + C with IgG-anti-α 1 -AT resulted in a blockade of their C3 receptor activity.…
Muscle adenylate kinase in Duchenne muscular dystrophy
1986
Abstract On the basis of electrophoretic and enzyme inhibition studies it was postulated that an aberrant adenylate kinase occurs in muscle and serum of patients with Duchenne muscular dystrophy (Schirmer, R.H. and Thuma, E. (1972) Biochim. Biophys. Acta 268, 92–97; Hamada, M. et al. (1981) Biochim. Biophys. Acta 660, 227–237; Hamada et al. (1985) J. Biol. Chem. 260, 11595–11602. On the basis of the following results we conclude that Duchenne muscular dystrophy patients do not possess an unusual adenylate kinase isoenzyme. (1) In muscle biopsies from five Duchenne patients, the electrophoretic mobility of adenylate kinase and the inhibition of the enzyme by P 1 , P 5 -di(adenosine-5′)pentap…