506 research outputs found
Binding of Oxovanadium(IV) Complexes to Blood Serum Albumins
In this work the binding of VIVO2+ and VIVO-complexes to
serum albumins {human serum albumin (HSA), bovine serum albumin
(BSA) and porcine serum albumin (PSA)} are studied using circular
dichroism (CD), electron paramagnetic resonance (EPR) and visible
absorption spectroscopy. The results confirm previous findings that
VIVO2+ occupies at least two types of binding sites on albumin: ‘the
strong vanadium binding site’ (designated by VBS1) and ‘the weak
vanadium binding sites’ (designated by VBS2). VBS1 binds 1 mol
equivalent of VIVO2+. On the other hand VBS2 correspond to binding
of several mol equivalents of VIVO, and studies done with PSA in the
presence of excess ZnII ions indicate that VSB2 corresponds to two
distinct types of sites. The hyperfine coupling constant Az for VIVO2+
binding at VBS2 on HSA and BSA are all very similar (~168 × 10-4
cm-1) but differ slightly on PSA (~166 × 10-4 cm-1) due to differences
in the binding sets. When (VIVO)-HSA systems are titrated with maltol
ternary species of (maltol)m(VIVO)mHSA and (maltol)2m(VIVO)mHSA
stoichiometry form which are clearly distinguishable from the binary
(VIVO)-HSA system by the type and intensity of the CD spectra
recorded. Changes are also observable in the intensity of the X-band
EPR spectra, but not much in the hyperfine coupling constants Az,
which are all in the range 166-167 × 10-4 cm-1. The results further
demonstrate that the presence of maltol may enhance the binding of
VIVO to albumin
MULTIDIMENSIONAL PEPTIDE/PROTEIN ANALYSIS AND IDENTIFICATION BY SEQUENCE DATABASE SEARCH USING MASS SPECTROMETRIC DATA
In order to generate proteomics data that are suitable to validate protein identification in complex mixtures using multidimensional liquid-chromatography-mass spectrometry approaches, we implemented an offline two-dimensional liquid chromatography method combining strong cation-exchange- and ion-pair reversed-phase chromatography followed by electrospray ionization tandem mass spectrormetry (ESI-MS/MS) for the analysis of a bovine serum albumin digest. The fragment ion spectra generated by ESI-MS/MS were subsequently analyzed via MASCOT database search. The obtained identification data were evaluated in terms of quality of protein/peptide identification by means of score values, reproducibility of identification in replicate measurements, distribution of tryptic peptides among different fractions, and overall number of unique identified proteins/peptides.
Finally, we improved the trapping conditions in the second dimension by using a more hydrophobic amphiphile in the loading buffer. The improvement was demonstrated by comparison of the obtained identification data, such as number of identified peptides, cumulative mowse scores and reproducibility of identification
Factors affecting protein synthesis in vitro in rabbit reticulocytes
Rabbit reticulocytes in vitro rapidly incorporate labeled amino acids into their proteins. The process is accelerated by the plasma of every mammal investigated and also by extracts of normal erythrocytes, rabbit reticulocytes, liver, spleen, and yeast (1). We have described two sets of stimulating factors: one of these sets consists of certain amino acids (1), the other of fructose-amino acids in liver (2-4). The latter set is ineffective without the addition of iron to the reaction medium. The effect of iron has been referred to in preceding publications (2-5), but without detail. After the necessity of adding iron was recognized, in order to obtain a maximal rate of protein synthesis the reaction mixture was improved further by adding to it certain substances which depend upon added iron for their effect. These increased the effect of plasma. Eventually the total (potential as well as actual) accelerating effects of plasma and liver extract were accounted for by known substances. This led to the devising of a reaction mixture formula in which the amino acid incorporation is about five times as fast as that observed when the cells are incubated in saline
Insect diversity and composition during the wet and dry seasons in three forest types of Johor, Malaysia
The insect diversity and abundance in three forest types namely: Endau Rompin
(pristine lowland forest) Gunung Ledang (pristine highland forest) and Bukit Soga
(degraded lowland forest) in Johor, Malaysia were studied. The study focused on
10 common insect orders. The objectives are (1) to investigate the composition
and abundance of insect morphospecies in three forest types; (2) to compare the
composition and abundance of insect morphospecies in the wet and dry seasons in
three forest types; and (3) to determine the dominant insect of the study sites.
There were four sampling methods employed as baited pitfall traps, aerial net,
manual collection and sweep net. The sampling methods were employed three
days in each location. The different insects sampled, were higher during the wet
season as compared to the dry season (diversity and abundance). Although Bukit
Soga lowland a degraded forest had the highest diversity of 52; and abundance of
112,081 individuals, it had the lowest Shannon weiner index of species diversity
and lowest evenness of (H’1.09 and evenness of 0.28). Gunung Ledang, had
lowest species diversity of 32 and abundance of 1,695 individuals but had the
highest H’of 2.34 and highest evenness of 0.68. Endau Rompin had 46 species
diversity and abundance of 70,821individuals and H’of 1.17and evenness of 0.30.
In highland forest the most diverse dominant insects were the butterflies
(Lepidoptera: Rhopalocera). Meanwhile ant, (Hymenoptera: Formicidae) was
more diverse in lowland forest than the highland forest. In all the three locations,
ant was most abundant. Since Jaccard similarity index was low between Gunung
Ledang and Bukit Soga (0.22); and between Gunung Ledang and Endau Rompin
(0.27) it is concluded that altitude had a greater effect on insect diversity. This is
supported by a two ways ANOVA analyses that showed insect diversity and
abundance between the two lowland forests (Endau Rompin and Bukit Soga) and
highland forest (Gunung Ledang) are significantly different. Difference between
the lowland forests was not significant. Generally, effect of wet and dry seasons
has no clear impact on diversity but abundance was higher during wet season
especially for ants (Hymenoptera: Formicidae)
Comparative studies on the interactions between human serum albumin, bovine serum albumin and cholesterol: ftir and fluorescence spectroscopy
The interaction of the human serum albumin (HSA), bovine serum albumin (BSA) with cholesterol has
been investigated. The basic binding interaction was studied by FTIR and fluorescence spectroscopy.
From spectral analysis cholesterol showed a strong ability to quench the intrinsic fluorescence of HSA
and BSA through a static quenching mechanism. The binding constant (k) between HSA and cholesterol
is estimated to be K=2.14 × 103 M-1 at 293 K while between BSA and cholesterol is estimated to be
K=.1.12 × 103 M-1 at the same temperature. FTIR spectroscopy with Fourier self-deconvolution technique
was used to determine the protein secondary structure and cholesterol binding mechanisms. The observed
spectral changes indicate a higher percentage of H-bonding between cholesterol and -helix compared to
the percentage of H-bonding to cholesterol and -sheets.This work is supported by the German
Research Foundation DFG grant No. DR228/24-
Activity of lactoperoxidase when adsorbed on protein layers
Lactoperoxidase (LPO) is an enzyme, which is used as an antimicrobial agent in a number of applications, e.g., food technology. In the majority of applications LPO is added to a homogeneous product phase or immobilised on product surface. In the latter case, however, the measurements of LPO activity are seldom reported. In this paperwe have assessed LPO enzymatic activity on bare and protein modified gold surfaces by means of electrochemistry. It was found that LPO rapidly adsorbs to bare gold surfaces resulting in an amount of LPO adsorbed of 2.9mg/m2. A lower amount of adsorbed LPO is obtained if the gold surface is exposed to bovine serum albumin, bovine or human mucin prior to LPO adsorption. The enzymatic activity of the adsorbed enzyme is in general preserved at the experimental conditions and varies only moderately when comparing bare gold and gold surface pretreated with the selected proteins. The measurement of LPO specific activity, however, indicate that it is about 1.5 times higher if LPO is adsorbed on gold surfaces containing a small amount of preadsorbed mucin in comparison to the LPO directly adsorbed on bare gold
Effects of Electrical Stimulation on Wound Closure in Mice with Experimental Diabetes Mellitus
The purpose of the present study was to examine the effect of electrical stimulation (ES) on the closure of full-thickness excisional wounds in mice with type-1 experimental diabetes mellitus (DM). Alloxon monohydrate (100mg/kg) was used to induce experimental DM in mole CD-1 mice (n = 88). Full-thickness skin excisions (1cm2) in diabetic (urine glucose \u3e 0) and non-diabetic (urine glucose = 0) mice were administered 1, 3, or 5 treatments of ES (200μs, 200 Hz) for 15 minutes, at 0 (sham), 5, 10, or 12.5 volts. Alloxon injection resulted in a positive urine glucose test in 48 mice yielding an induction rate for DM of 54.5 percent. All groups exhibited decreases in wound length, perimeter, and surface area between days 2 and 16 following the creation of wounds. Non-diabetic wounds treated with ES hod the greatest percentage (60%) of closure. Diabetic wounds treated with ES hod a greater percentage of cloÂsure (36%) compared with sham-treated diabetic animals (12.5%). Treatment of wounds with the highest voltage of ES (12.5V) produced significant (P \u3c 0.01) decreases in the surface area, and significant (P \u3c 0.01) changes in the shapes of wounds in both diabetic and non-diabetic animals compared with sham-treated animals. These results support the clinical use of this adjunctive therapy to accelerate the closure of ulcers due to OM
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