scholarly journals Protease-Dependent Fractional Mass and Peptide Properties

2008 ◽  
Vol 14 (5) ◽  
pp. 311-317 ◽  
Author(s):  
Harald Barsnes ◽  
Ingvar Eidhammer ◽  
Véronique Cruciani ◽  
Svein-Ole Mikalsen
Keyword(s):  
Random Distribution ◽  
Mass Difference ◽  
Regression Line ◽  
Mass Spectrometric ◽  
Peptide Mass Fingerprint ◽  
Chemical Effects ◽  
Peptide Mass ◽  
Physico Chemical ◽  
Human Proteins ◽  
Fractional Mass

Mass spectrometric analyses of peptides mainly rely on cleavage of proteins with proteases that have a defined specificity. The specificities of the proteases imply that there is not a random distribution of amino acids in the peptides. The physico–chemical effects of this distribution have been partly analyzed for tryptic peptides, but to a lesser degree for other proteases. Using all human proteins in Swiss-Prot, the relationships between peptide fractional mass, pI and hydrophobicity were investigated. The distribution of the fractional masses and the average regression lines for the fractional masses were similar, but not identical, for the peptides generated by the proteases trypsin, chymotrypsin and gluC, with the steepest regression line for gluC. The fractional mass regression lines for individual proteins showed up to ±100 ppm in mass difference from the average regression line and the peptides generated showed protease-dependent properties. We here show that the fractional mass and some other properties of the peptides are dependent on the protease used for generating the peptides. With the increasing accuracy of mass spectrometry instruments, it is possible to exploit the information embedded in the fractional mass of unknown peaks in peptide mass fingerprint spectra.

scholarly journals Distribution of 226Ra, 232Th, and 40K in rice plant components and physico-chemical effects of soil on their transportation to grains

2015 ◽  
Vol 8 (3) ◽  
pp. 300-310 ◽  
Author(s):  
Mohammed Saad Alsaffar ◽  
Mohamad Suhaimi Jaafar ◽  
Norlaili Ahmad Kabir ◽  
Nisar Ahmad
Keyword(s):  
Rice Plant ◽  
Chemical Effects ◽  
Physico Chemical ◽  
Plant Components

scholarly journals Antimicrobial and physico-chemical effects of essential oils on fermented milk during preservation

2016 ◽  
Vol 99 (1) ◽  
pp. 9467 ◽  
Author(s):  
Tovidé Sènou Noël ◽  
Adeoti Kifouli ◽  
Yèhouénou Boniface ◽  
Dahouénon-Ahoussi Edwige ◽  
Baba- Moussa Farid ◽  
...  
Keyword(s):  
Essential Oils ◽  
Fermented Milk ◽  
Chemical Effects ◽  
Physico Chemical

Protein mass measurement combined with mass spectrometric sequencing of protein digests for detection and characterization of protein modifications1

2006 ◽  
Vol 84 (7) ◽  
pp. 986-997 ◽  
Author(s):  
Chengjie Ji ◽  
Zhengping Wang ◽  
Liang Li
Keyword(s):  
Mass Spectrometry ◽  
Gel Electrophoresis ◽  
Protein Modification ◽  
Mass Spectrometric ◽  
Maldi Ms ◽  
Intact Protein ◽  
Protein Mass ◽  
Cell Extracts ◽  
Peptide Mass

A method for the characterization of modifications of low molecular weight proteins (<20 kDa) extracted from a microorganism based on the use of multiple separation tools and mass spectrometric techniques is described. In this method, intact proteins from cell extracts are first separated and fractionated by liquid chromatography (LC). Individual fractions are then analyzed by matrix-assisted laser desorption ionization (MALDI) mass spectrometry (MS) to provide intact protein mass information. The fractions are further characterized by using trypsin digestion and LC electrospray ionization (ESI) MS/MS analysis of the resultant peptides to identify the proteins. Gel electrophoresis of a fraction is also carried out to estimate the molecular masses of the proteins. The gel bands are identified by in-gel digestion and peptide mass mapping and sequencing using MALDI-MS and MALDI-MS/MS. The combined information generated from these experiments is interpreted for detecting and characterizing modified proteins. This method has been developed and applied to the analysis of posttranslational modifications (PTMs) of low-mass proteins (5–20 kDa) extracted from a relatively well-characterized microorganism, Escherichia coli. Using this method, not only previously reported PTMs involving acetylation, methylation, oxidation, and the removal of signal peptides, but also two novel PTMs, namely loss of N-terminal Met-Thr-Met (MTM) and hydroxylation of arginine, were identified. It is envisaged that this method should be applicable to other relatively simple microorganisms for the discovery of new PTMs.Key words: top-down proteomics, protein modification, HPLC, gel electrophoresis, tandem mass spectrometry.

scholarly journals Structural and physico-chemical effects of disease and non-disease nsSNPs on proteins

2015 ◽  
Vol 32 ◽  
pp. 18-24 ◽  
Author(s):  
Tugba G Kucukkal ◽  
Marharyta Petukh ◽  
Lin Li ◽  
Emil Alexov
Keyword(s):  
Chemical Effects ◽  
Physico Chemical

Nuclear recoil reactions in organomanganese compounds. IV. Fulvalenehexacarbonyldimanganese

1970 ◽  
Vol 48 (10) ◽  
pp. 1614-1615 ◽  
Author(s):  
I. G. DeJong ◽  
D. R. Wiles
Keyword(s):  
Reaction Zone ◽  
Neutron Capture ◽  
Radiochemical Yield ◽  
Mass Spectrometric ◽  
Nuclear Recoil ◽  
Carbonyl Ligands ◽  
Chemical Effects ◽  
Mass Spectrometric Evidence ◽  
Organomanganese Compounds

The chemical effects of neutron capture have been studied in fulvalenehexacarbonyldimanganese, in order to determine whether or not the ring–ring bond survives nuclear recoil. Retention in the parent form (9.1 %) is comparable to that in other organomanganese compounds, while the radiochemical yield of CpMn(CO)3, the "monomer", is very much lower (0.2%). This suggests that the inter-ring bond is not broken under the conditions in the reaction zone. The formation of radiomanganese compounds with several carbonyl ligands (4.7%) is in accord with mass spectrometric evidence, which suggests that CO may be readily available in the reaction zone.

scholarly journals Identification of post-translational modifications resulting from LHbeta polymorphisms by matrix-assisted laser desorption time-of-flight mass spectrometric analysis of pituitary LHbeta core fragment

2003 ◽  
Vol 30 (2) ◽  
pp. 239-252 ◽  
Author(s):  
ES Jacoby ◽  
AT Kicman ◽  
RK Iles
Keyword(s):  
Mass Spectra ◽  
Time Of Flight ◽  
Laser Desorption ◽  
Mass Spectrometric ◽  
Mass Spectrometric Analysis ◽  
Spectrometric Analysis ◽  
Core Fragment ◽  
Peptide Mass ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Metabolism of the human chorionic gonadotrophin (hCG)- and LHbeta-subunits (hCGbeta, LHbeta) terminates with the urinary excretion of core fragment (hCGbetacf, LHbetacf) molecules that retain antigenic shape and constituent N-linked carbohydrate moieties. We have previously demonstrated the resolved mass spectra of hCGbetacf, from which the carbohydrate moieties present at two N-linked glycosylation sites were identified. LHbetacf was subjected to the same mass spectrometric analysis. As LHbeta shares 82% homology with hCGbeta but possesses only one glycosylation consensus site a simpler spectral fingerprint of LHbetacf glycoforms was expected. LHbetacf was reduced with dithiothreitol and analysed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. Glycoforms were predicted by subtracting the peptide mass from the m/z values of the observed peaks and then sequentially subtracting the masses of the monosaccharide residues of hCGbeta N-linked carbohydrates reported in the literature. The mass spectra of LHbetacf revealed a broad single peak ranging from m/z 8700 to 10 700. Following reduction, this peak was replaced by a set of partially resolved peaks between m/z 4130 and 5205 corresponding to glycosylated forms of the peptide LHbeta6-40. A peak at m/z 4252.2 corresponded to the non-glycosylated peptide LHbeta55-93. Remaining peaks indicated that the pooled sample comprised a wide set of glycoforms, contained LHbetacf with two N-linked carbohydrate moieties and indicated evidence of further glycosylation due to amino acid substitution in polymorphic variants. This is evidence that a single nucleotide polymorphism alters the post-translational modification of a protein and hence its structural phenotype.

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