Enzyme activity and cation exchange as tools for the study of the conformation of proteins adsorbed on mineral surfaces

2007 ◽  
pp. 59-63 ◽  
Author(s):  
H. Quiquampoix ◽  
P. Chassin ◽  
R. G. Ratcliffe
Keyword(s):  
Enzyme Activity ◽  
Cation Exchange ◽  
Mineral Surfaces

scholarly journals Peroxidase and peroxidase-oxidase activities of isolated human myeloperoxidases

1987 ◽  
Vol 242 (3) ◽  
pp. 673-680 ◽  
Author(s):  
B E Svensson ◽  
K Domeij ◽  
S Lindvall ◽  
G Rydell
Keyword(s):  
Enzyme Activity ◽  
Cation Exchange ◽  
Gel Filtration ◽  
Exchange Chromatography ◽  
Relative Molecular Mass ◽  
Cation Exchange Chromatography ◽  
Healthy Donors ◽  
Activity Measurements ◽  
Molecular Masses ◽  
Sites Of Action

Isolated neutrophils from healthy donors were used for the isolation of four highly purified forms of myeloperoxidase as determined by spectral (A430/A280 ratio 0.80-0.87) and enzyme-activity measurements. Although the myeloperoxidases exhibited different elution profiles on cation-exchange chromatography, gel filtration indicated similar relative molecular masses. When these forms were assayed for peroxidase and peroxidase-oxidase activities with several substrates, they all exhibited virtually the same specific activities. These results suggest that possible functional differences between the enzymes may be related to differences in their sites of action rather than to differences in enzyme activity. Myeloperoxidase from a patient with chronic myeloid leukaemia also revealed a similar heterogeneity on cation-exchange chromatography. However, this myeloperoxidase contained in addition one form with a lower and one form with a higher relative molecular mass, as indicated by gel-filtration chromatography.

scholarly journals Interactions between Cationic Dye Toluidine Blue and Fibrous Clay Minerals

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 708
Author(s):  
Qingfeng Wu ◽  
Kristen Carlson ◽  
Qi Cheng ◽  
Xisen Wang ◽  
Zhaohui Li
Keyword(s):  
Cation Exchange ◽  
Toluidine Blue ◽  
Electrostatic Interactions ◽  
Cationic Dyes ◽  
Strong Interactions ◽  
Cationic Dye ◽  
Mineral Surfaces ◽  
Dynamic Simulations ◽  
Experimental Conditions ◽  
Maya Blue

Interactions between cationic dyes and negatively charged mineral surfaces have long attracted great attention from clay mineralogists, environmental scientists, and chemical engineers. In this study, the interactions between a cationic dye toluidine blue (TB) and palygorskite and sepiolite were investigated under different experimental conditions. The results showed that in addition to cation exchange, the specific surface area (SSA) of the minerals, particularly the formation of dimer molecules on the surface of both minerals, also accounted for the much higher TB uptake in comparison to their cation exchange capacities (CEC). The TB molecules were sorbed to the external surfaces, as no d-spacing expansion was observed in X-ray diffraction analyses. FTIR analyses showed strong interactions between the C=N or N-(CH3)2 group and the mineral surfaces, suggesting net electrostatic interactions if either of these functional groups bears a positive charge. Results from molecular dynamic simulations suggested dense monolayer TB formation on palygorskite because of its limited SSA and large CEC values. In comparison, a loosely dimeric formation was revealed on sepiolite for its large SSA and limited CEC values. Therefore, palygorskite is a better carrier for the sorption of cationic dyes, as evidenced by Maya blue paintings.

EFFECTS OF SOME CHEMICAL TREATMENTS ON K/Ca CATION EXCHANGE SELECTIVITY OF LAYER SILICATES

1972 ◽  
Vol 52 (2) ◽  
pp. 151-161 ◽  
Author(s):  
M. A. ARSHAD ◽  
P. M. HUANG ◽  
R. J. ST. ARNAUD
Keyword(s):  
Cation Exchange ◽  
Amorphous Materials ◽  
Mineral Surfaces ◽  
Layer Silicates ◽  
Chemical Treatments ◽  
Soil Clays ◽  
Mineral Components ◽  
Ca Ions ◽  
Oxalate Extraction ◽  
Exchange Selectivity

The effects of chemical treatments commonly employed to remove amorphous materials, on the K/Ca cation exchange selectivity (CES) of montmorillonite, kaolinite, chlorite, vermiculite, biotite, muscovite, and soil clays were studied. The K/Ca CES values for biotite and muscovite decreased appreciably upon peroxidation. Both the Na–dithionite–citrate–bicarbonate and boiling 0.5 N NaOH dissolution treatments resulted in a substantial increase in the K/Ca CES of biotite and muscovite. This was attributable to increases in the wedge-zone sites resulting from partial K-depletion of these minerals. Furthermore, the release of structural cations and their subsequent precipitation on mineral surfaces appears to have resulted in the "preferential occupation" of Ca-adsorbing sites and thus contributed to the lower selectivity of Ca ions. However, these two treatments affected the K/Ca CES of illite slightly. Acid NH4-oxalate extraction reduced the K/Ca CES values for all layer silicates investigated except chlorite for which the reverse was true. Selectivity of Ca and the CEC of illite were substantially increased by this treatment. The data suggested that the naturally occurring amorphous inorganic and organic constituents may have higher selectivity towards Ca relative to K. However, the degree of variation in the K/Ca CES seems to be further controlled by the amount, nature, and composition of amorphous materials and the mechanisms by which they are associated with the crystalline mineral components.

Morphological and biochemical analyses of changes in rat hepatocytes related to wine and ethanol consumption

1984 ◽  
Vol 42 ◽  
pp. 232-233
Author(s):  
S.M. Geyer ◽  
C.L. Mendenhall ◽  
J.T. Hung ◽  
E.L. Cardell ◽  
R.L. Drake ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Enzyme Activity ◽  
Malic Enzyme ◽  
Smooth Endoplasmic Reticulum ◽  
Rat Hepatocytes ◽  
Mature Male ◽  
Treatment Groups ◽  
Malic Enzyme Activity ◽  
Biochemical Analyses

Thirty-three mature male Holtzman rats were randomly placed in 3 treatment groups: Controls (C); Ethanolics (E); and Wine drinkers (W). The animals were fed synthetic diets (Lieber type) with ethanol or wine substituted isocalorically for carbohydrates in the diet of E and W groups, respectively. W received a volume of wine which provided the same gram quantity of alcohol consumed by E. The animals were sacrificed by decapitation after 6 weeks and the livers processed for quantitative triglycerides (T3), proteins, malic enzyme activity (MEA), light microscopy (LM) and electron microscopy (EM). Morphometric analysis of randomly selected LM and EM micrographs was performed to determine organellar changes in centrilobular (CV) and periportal (PV) regions of the liver. This analysis (Table 1) showed that hepatocytes from E were larger than those in C and W groups. Smooth endoplasmic reticulum decreased in E and increased in W compared to C values.

Scanning Electron Microscope Study of Bacteria on Mineral Surfaces

1976 ◽  
Vol 34 ◽  
pp. 130-131
Author(s):  
V.K. Berry
Keyword(s):  
Oxidation Reaction ◽  
Electron Microscope Study ◽  
Elemental Sulfur ◽  
Thiobacillus Ferrooxidans ◽  
Physical Contact ◽  
Metal Sulfides ◽  
Low Grade ◽  
Mineral Surfaces ◽  
Mineral Surface ◽  
Scanning Electron Microscope Study

There are two strains of bacteria viz. Thiobacillus thiooxidansand Thiobacillus ferrooxidanswidely mentioned to play an important role in the leaching process of low-grade ores. Another strain used in this study is a thermophile and is designated Caldariella .These microorganisms are acidophilic chemosynthetic aerobic autotrophs and are capable of oxidizing many metal sulfides and elemental sulfur to sulfates and Fe2+ to Fe3+. The necessity of physical contact or attachment by bacteria to mineral surfaces during oxidation reaction has not been fairly established so far. Temple and Koehler reported that during oxidation of marcasite T. thiooxidanswere found concentrated on mineral surface. Schaeffer, et al. demonstrated that physical contact or attachment is essential for oxidation of sulfur.

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