scholarly journals Phosphatase activity of Poa pratensis seeds. I. Preliminary studies on acid phosphatase II

2015 ◽  
Vol 42 (3) ◽  
pp. 369-377
Author(s):  
I. Lorenc-Kubis ◽  
B. Morawiecka

Acid phosphatase (EC 3.1.3.2) was extracted with 0.1 M sodium acetate buffer pH 5.1 from <i>Poa pratensis</i> seeds, and separated into three fractions by chromatography on DEAE cellulose. The highest activity was found in fraction Il-b (acid phosphatase II). The activity of the enzyme was optimal at pH 4.9. It hydrolyzed p-nitrophenyl phosphate most readily among the various phosphomonoesters examined. Acid phosphatase II showed also a high activity toward β-naphtyl phosphate and phenyl phosphate, very low activity towards β-glycero phosphate, 5'-GMP and no activity with glucose-1 phosphate. The enzyme was inhibited by Ca<sup>2+</sup> and fluoride, but activated by Mg<sup>2+</sup>. EDTA had no influence on the activity of the enzyme.

2015 ◽  
Vol 47 (4) ◽  
pp. 441-453 ◽  
Author(s):  
Eleonora Wieczorek ◽  
Janina Wiśniewska ◽  
Bronisława Morawiecka

Acid phosphatase and ribonuclease extracted with 0.1 M sodium acetate buffer, pH 5.1 from Dactylis glomerata seeds, and partially purified by means of 70% ethanol precipitation showed electrophoretic and Chromatographic heterogeneity. After chromatography on DEAE-cellulose acid phosphatase and ribonuclease were separated into four peaks. Nonadsorbing acid phosphatase on DEAE-cellulose (peak I) was separated into four peaks on CM-cellulose. The highest activity (11 units/mg) was found in fraction b (acid phosphatase Ib). The enzyme was activated by Mg<sup>2+</sup>, Ca<sup>2+</sup>, Li<sup>+</sup>, Cs<sup>+</sup>, K<sup>+</sup> ions and inhibited by Cu<sup>2+</sup>, Zu<sup>2+</sup>, F<sup>-</sup> and Mo<sup>-6</sup> at optimum pH 5.0. Strong absorbing ribonuclease on DEAE-cellulose (peak IV) was further separated on G-200 Sephadex into two molecular forms: RN-asa1 and RN-ase2. Ribonuclease l, a thermolabile enzyme with specific activity 807 units/mg, showed an optimal activity at pH 4.8-5.1.


Author(s):  
Janet H. Woodward ◽  
D. E. Akin

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.


1979 ◽  
Vol 42 (05) ◽  
pp. 1452-1459 ◽  
Author(s):  
Robert H Yue ◽  
Toby Starr ◽  
Menard M Gertler

SummaryCommercial porcine heparin can be separated into three distinct subtractions by using DEAE-cellulose chromatography and a stepped salt gradient. Gram quantities of heparin can be fractionated by this technique. All three heparin subtractions can accelerate the inhibition of thrombin by antithrombin III with different efficiency. The specific activities of the high activity heparin, intermediate activity heparin and low activity heparin are 228 units/mg, 142 units/mg and 95 units/mg, respectively. Both the uronic acid content and the quantity of N-SO4 for all three heparin subfractions have been evaluated. The high activity heparin has the lowest uronic acid and N-SO4 content. The successful separation of commercial heparin into three distinct subfractions by means of ion-exchange chromatography suggests that the net charge on these three heparin components will serve as a model system in the elucidation of the structure and activity relationship to the biological function of heparin.


1986 ◽  
Vol 239 (1) ◽  
pp. 155-162 ◽  
Author(s):  
M Okada ◽  
K Owada ◽  
H Nakagawa

A [phosphotyrosine]protein phosphatase (PTPPase) was purified almost to homogeneity from rat brain, with [32P]p130gag-fps, an oncogene product of Fujinami sarcoma virus, as substrate. The characteristics of the purified preparation of PTPPase were as follows: the enzyme was a monomer with a molecular mass of 23 kDa; its optimum pH was 5.0-5.5; its activity was not dependent on bivalent cations; its activity was strongly inhibited by sodium vanadate, but was not inhibited by ZnCl2, L(+)-tartrate or NaF; it catalysed the dephosphorylation of [32P]p130gag-fps, [[32P]Tyr]casein, p-nitrophenyl phosphate and L-phosphotyrosine, but did not hydrolyse [[32P]Ser]tubulin, L-phosphoserine, DL-phosphothreonine, 5′-AMP, 2′-AMP or beta-glycerophosphate significantly. During the purification, most of the PTPPase activity was recovered in distinct fractions from those of conventional low-molecular-mass acid phosphatase (APase), which was reported to be a major PTPPase [Chernoff & Li (1985) Arch. Biochem. Biophys. 240, 135-145], from DE-52 DEAE-cellulose column chromatography, and those two enzymes could be completely separated by Sephadex G-75 column chromatography. APase also showed PTPPase activity with [32P]p130gag-fps, but the specific activity was lower than that of PTPPase with molecular mass of 23 kDa, and it was not sensitive to sodium vanadate. These findings suggested that PTPPase (23 kDa) was the major and specific PTPPase in the cell.


1963 ◽  
Vol 41 (4) ◽  
pp. 1073-1078 ◽  
Author(s):  
J. M. Neelin

The effect of pH on gradient starch gel electrophoresis of the venoms of Crotalus adamanteus and Naja flava has been examined. Sodium acetate buffer, pH 4.1, ionic strength 0.020, appeared most effective for resolution of the former venom, and acetate buffer, pH 4.7, or cacodylate buffer, pH 6.0, for the latter. Two-dimensional starch gel electrophoresis resolved at least 20 zones from the crotaline venom and 11 from the colubrid. Two zones of hemolytic activity were separated from each venom: in C. adamanteus the less cationic zone included possibly two or more acidic proteins; the corresponding zone of N. flava was more basic, more homogeneous, and more active under the conditions of assay.


Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 160
Author(s):  
Jelena Milinovic ◽  
Ágata Alveirinho Dias ◽  
Ana I. Janeiro ◽  
Manuel F. C. Pereira ◽  
Sofia Martins ◽  
...  

The on-board identification of ore minerals during a cruise is often postponed until long after the cruise is over. During the M127 cruise, 21 cores with deep-seafloor sediments were recovered in the Trans-Atlantic Geotraverse (TAG) field along the Mid Atlantic Ridge (MAR). Sediments were analyzed on-board for physicochemical properties such as lightness (L*), pH and Eh. Selected samples were studied for mineral composition by X-ray powder diffraction (XRD). Based on XRD data, sediment samples were separated into high-, low- and non-carbonated. Removal of carbonates is a common technique in mineralogical studies in which HCl is used as the extraction agent. In the present study, sequential extraction was performed with sodium acetate buffer (pH 5.0) to remove carbonates. The ratio between the highest calcite XRD reflection in the original samples (Iorig) vs its XRD-reflection in samples after their treatment with the buffer (Itreat) was used as a quantitative parameter of calcite removal, as well as to identify minor minerals in carbonated samples (when Iorig/Itreat > 24). It was found that the lightness parameter (L*) showed a positive correlation with calcite XRD reflection in selected TAG samples, and this could be applied to the preliminary on-board determination of extraction steps with acetate buffer (pH 5.0) in carbonated sediment samples. The most abundant minerals detected in carbonated samples were quartz and Al- and Fe-rich clays. Other silicates were also detected (e.g., calcic plagioclase, montmorillonite, nontronite). In non-carbonated samples, Fe oxides and hydroxides (goethite and hematite, respectively) were detected. Pyrite was the dominant hydrothermal mineral and Cu sulfides (chalcopyrite, covellite) and hydrothermal Mn oxides (birnessite and todorokite) were mineral phases identified in few samples, whereas paratacamite was detected in the top 20 cm of the core. The present study demonstrates that portable XRD analysis makes it possible to characterize mineralogy at cored sites, in particular in both low- and high-carbonated samples, before the end of most cruises, thus enabling the quick modification of exploration strategies in light of new information as it becomes available in near-real time.


Author(s):  
Ragnar Fänge

Activities of phosphomonoesterases were measured at acid and at alkaline reaction (pH 4–5 or 9–65) in homogenates of elasmobranch tissues especially lymphomyeloid structures. The animals were dogfish (Scyliorhinus caniculd) and two species of ray (Raja brachyura, R. naevus). Acid phosphatase activity was high in the epigonal tissue, Leydig's organ, the spleen and the thymus. High activity was also found in the pancreas and the kidney, whereas skeletal and cardiac muscle showed low values. The activity of alkaline phosphatase was very high in the kidney and relatively low in other tissues. Ultrasonification of homogenates from the dogfish resulted in increase of acid phosphatase activity but had little effect on alkaline phosphatase activity. The high activity of acid phosphatase in lymphomyeloid tissue may be due to the presence of large numbers of various types of leucocytes.


1970 ◽  
Vol 118 (5) ◽  
pp. 703-712 ◽  
Author(s):  
G. T. Stevenson ◽  
K. J. Dorrington

1. Both the γ and light peptide chains of human pooled and myeloma immunoglobulin G can be prepared as non-aggregating dimers at pH5.4 in 4mm-sodium acetate buffer. The dimeric state is maintained by non-covalent bonds, since the formation of interchain disulphide bonds was prevented by alkylation of the thiol groups. In the case of the light chains there is some evidence that the dimers are in equilibrium with a small amount of monomer. 2. When such dimers of the γ and light chains are mixed at pH5.4 in 4mm-sodium acetate buffer they combine rapidly, yielding a product that resembles the original immunoglobulin G in its physicochemical and antigenic properties. However, the original optical rotatory dispersion spectrum was regained only with the homogeneous myeloma protein. The recombined pooled immunoglobulin G had a spectrum slightly different from the original, suggesting that at least some of the recombinant molecules had not regained native conformations. 3. Dimers of γ chains stabilized by interchain disulphide bonds were able to recombine with light chains. However, light chains stabilized in the dimeric state by interchain disulphide bonds would not combine with γ chains. 4. The chains of rabbit immunoglobulin G behave similarly to the human chains in this system, apart from the alkylated light chains showing clearer evidence of monomeric components.


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