scholarly journals Studies of the limited degradation of mucus glycoproteins. The effect of dilute hydrogen peroxide

1983 ◽  
Vol 211 (2) ◽  
pp. 323-332 ◽  
Author(s):  
J M Creeth ◽  
B Cooper ◽  
A S R Donald ◽  
J R Clamp
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Simple Structure ◽  
Peptide Bond ◽  
Low Molecular Weight ◽  
Amino Acid Residues ◽  
Oligosaccharide Moiety ◽  
Small Gain ◽  
Mucus Glycoproteins

1. The action of dilute H2O2 on a series of ovarian-cyst glycoproteins and glycopolypeptides was investigated. 2. Both native glycoproteins and the glycopolypeptides were carbohydrate-rich, of relatively low molecular weight and of simple structure. 3. At pH 5.6 and 37 degrees C, exposure to H2O2 for a limited time brought about a partial degradation, the molecular weight being decreased by 2-4-fold. 4. Carbohydrate analysis showed very little change in the oligosaccharide moiety, apart from a small decrease in sialic acid in some samples. 5. Amino acid analysis showed minor changes in serine, threonine and proline contents, but almost total loss of histidine. Concomitantly, there was a small gain in aspartic acid. 6. Myosin, examined at both pH 5.7 and 6.7, exhibited generally similar behaviour, there being losses of other amino acid residues as well as histidine: the viscosity was decreased to a low value, and a range of peptides of widely varying size was produced. 7. It is suggested that attack on the histidine residue, with partial conversion into aspartic acid, is accompanied by scission of the histidyl peptide bond.

scholarly journals Characterization of Trypsin Inhibitor in Florunner Peanut Seeds (Arachis hypogaea L.)1

1988 ◽  
Vol 15 (2) ◽  
pp. 81-84 ◽  
Author(s):  
E. M. Ahmed ◽  
J. A. Applewhite
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Arachis Hypogaea ◽  
Trypsin Inhibitor ◽  
Low Molecular Weight ◽  
Arachis Hypogaea L ◽  
Amino Acid Profiles ◽  
Low Levels

Abstract Florunner peanut seeds contained five trypsin isoinhibitors. Amino acid profiles of the trypsin inhibitors fraction showed high levels of aspartic acid, half-cystine and serine and low levels of histidine and tyrosine. The molecular weight of the inhibitor was 8.3 KDa. The presence of multiforms of this inhibitor, its low molecular weight and the high amount of half-cystine indicate that peanut trypsin inhibitor is of the Bowman-Birk type.

scholarly journals The structure of a glycopeptide isolated from the yeast cell wall

1968 ◽  
Vol 109 (3) ◽  
pp. 419-432 ◽  
Author(s):  
R. Sentandreu ◽  
D. H. Northcote
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Cell Wall ◽  
Amino Acid ◽  
Yeast Cell ◽  
Aspartic Acid ◽  
Yeast Cell Wall ◽  
Low Molecular Weight ◽  
Elimination Reaction ◽  
Sephadex Column

1. Glycopeptides containing mannose were extracted from isolated yeast cell walls by ethylenediamine and purified by treatment with Pronase and fractionation on a Sephadex column. 2. A glycopeptide that appeared homogeneous on electrophoresis and ultracentrifugation had a molecular weight of 76000, and contained a high-molecular-weight mannan and approx. 4% of amino acids. 3. The amino acid composition of the peptide was determined. It was rich in serine and threonine and also contained glucosamine. No cystine and methionine were detected. 4. The glycopeptide underwent a β-elimination reaction when treated with dilute alkali at low temperatures. The reaction resulted in the release of mannose, mannose disaccharides and possibly other low-molecular-weight mannose oligosaccharides. During the β-elimination reaction the dehydro derivatives of serine and threonine were formed. One of the linkages between carbohydrate and amino acids in the glycopeptide is an O-mannosyl bond from mannose and mannose oligosaccharides to serine and threonine. 5. After the β-elimination reaction the bulk of the mannose in the form of the large mannan component was still covalently linked to the peptide. This polysaccharide was therefore attached to the amino acids by a linkage different from the O-mannosyl bonds to serine and threonine that attach the low-molecular-weight sugars. 6. Mannan was prepared from the glycopeptide and from the yeast cell wall by treatment of the fractions with hot solutions of alkali. The mannan contained aspartic acid and glucosamine and some other amino acids. The aspartic acid and glucosamine were present in equimolar amounts; the aspartic acid was the only amino acid present in an amount equivalent to that of glucosamine. Thus there is the possibility of a linkage between the mannan and the peptide via glucosamine and aspartic acid. 7. Mannose 6-phosphate was shown to be part of the mannan structure. Information about the structure of the mannan and the linkage of the glucosamine was obtained by periodate oxidation studies. 8. The glucosamine present in the glycopeptide could not be released by treatment with an enzyme preparation obtained from the gut of Helix pomatia. This enzyme released glucosamine from the intact cell wall. Thus there are probably at least two polymers containing glucosamine in the cell wall. 9. The biosynthesis of the mannan polymer in the yeast cell wall is discussed with regard to the two types of carbohydrate–amino acid linkages found in the glycoprotein.

The amino acid sequence of wheat β-purothionin

1976 ◽  
Vol 54 (10) ◽  
pp. 835-842 ◽  
Author(s):  
A. S. Mak ◽  
B. L. Jones
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Primary Structure ◽  
Basic Protein ◽  
Viscum Album ◽  
Low Molecular Weight ◽  
Amino Acid Residues ◽  
Basic Proteins ◽  
Considerable Homology

The complete amino acid sequence of β-purothionin, a low molecular weight, very basic, protein isolated from wheat endosperm material, has been determined. β-purothionin is toxic to some bacteria, to yeasts, and to animals when injected. The protein contains 45 amino acid residues and has a molecular weight of 4913. The 8 cysteine and 10 basic residues are distributed throughout the molecule. The primary structure of the protein shows considerable homology to those of the viscotoxins, which are toxic, small, basic proteins found in the leaves and stems of European mistletoe (Viscum album L.).

The Nature of the Chelate Structures Formed by Copper(II) and Ovalbumin in the Biuret Reaction

1963 ◽  
Vol 16 (6) ◽  
pp. 989 ◽  
Author(s):  
AC Jennings
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Alkaline Solution ◽  
Polypeptide Chain ◽  
Chemical Reactivity ◽  
Spectrophotometric Study ◽  
Low Molecular Weight ◽  
Amino Acid Residues ◽  
Heterogeneous Mixture

A spectrophotometric study was made of the interaction, in alkaline solution, of copper(II) with ovalbumin and several ligands of low molecular weight at several different atomic ratios of nitrogen/copper. The results indicate that the absorbance and chemical reactivity of the ovalbumin-copper(II) complex cannot be attributed to the presence of one particular chelate structure. It is suggested that the ovalbumin-copper(II) complex is a heterogeneous mixture of chelate structures in which the copper(II) is bonded to oxygen (in the enolate form) and nitrogen atoms in the several different combinations possible within the same polypeptide chain. It is also suggested that the actual arrangement of bonds in any one chelate structure is probably determined by both the nature of the amino acid residues and the configuration of the ovalbumin molecule in the immediate vicinity.

scholarly journals The complete amino acid sequence of the low molecular weight cytosolic acid phosphatase

1989 ◽  
Vol 264 (5) ◽  
pp. 2560-2567
Author(s):  
G Camici ◽  
G Manao ◽  
G Cappugi ◽  
A Modesti ◽  
M Stefani ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Acid Phosphatase ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Low Molecular Weight ◽  
Complete Amino Acid Sequence

Normal Mature Human Enamel Protein

1979 ◽  
Vol 58 (2_suppl) ◽  
pp. 986-987 ◽  
Author(s):  
A. Belcourt
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Gel Electrophoresis ◽  
Protein Concentration ◽  
Polyacrylamide Gel Electrophoresis ◽  
Organic Matrix ◽  
Low Molecular Weight ◽  
Human Enamel ◽  
Weak Density ◽  
Enamel Protein

Pure enamel was prepared using an original microdissection technic. Protein concentration was 375 μg per gram of enamel. Polyacrylamide gel electrophoresis showed a single fast-migrating zone containing a thin double band. Ultracentrifugation studies suggested that the proteins were of low molecular weight or of weak density. Absorption spectra showed a strong absorbance at 260nm. Amino acid analyses yielded a composition of 25% Gly, 13.5% Glu, 11% Ser, 11% Pro, 2% Cys and 2% Hyp. A glucidic content of 15% was estimated and glucose, galactose, mannose and fucose were identified. The organic matrix of enamel seemed to be constituted of two major glycoproteins probably fibrous but different from keratin.

The C-terminal sequence of amino acid residues of κ-casein isolated from buffalo's milk

1967 ◽  
Vol 34 (1) ◽  
pp. 85-88 ◽  
Author(s):  
M. H. Abd El-Salam ◽  
W. Manson
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Amino Acid ◽  
Peptide Chain ◽  
Amino Acid Residues ◽  
Terminal Sequence ◽  
Carboxypeptidase A ◽  
Phosphorous Content ◽  
Single Peptide

SummaryWhen κ-casein from buffalo's milk was treated with carboxypeptidase A (EC 3. 4. 2. 1),4 amino acids, valine, threonine, serine and alanine were released from the protein in a manner consistent with the view that they originate in the C-terminal sequence of a single peptide chain. The amounts produced suggest a minimum molecular weight for buffalo κ-casein of approximately 17000, in agreement with the value calculated from the phosphorous content on the basis of the presence of 2 phosphorus atoms/molecule. A comparison is made with the C-terminal sequence reported for bovine κ-casein.

scholarly journals Sea urchin (Anthocidaris crassispina) egg zinc-binding protein. Cellular localization, purification and characterization

1983 ◽  
Vol 211 (1) ◽  
pp. 109-118 ◽  
Author(s):  
H Ohtake ◽  
T Suyemitsu ◽  
M Koga
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Sea Urchin ◽  
Cellular Localization ◽  
Binding Protein ◽  
Gel Permeation Chromatography ◽  
Total Amino Acid ◽  
Amino Acid Residues ◽  
Gel Permeation ◽  
Anthocidaris Crassispina

Gel-filtration analysis of cytosol fraction obtained from unfertilized sea-urchin (Anthocidaris crassispina) eggs on Sephadex G-75 revealed the presence of two Zn-binding-protein fractions. The major Zn-binding protein fraction had a low molecular weight and a low absorbance at 280 nm, properties similar to those of the metallothionein found in the regenerating rat liver. These fractions were further purified by DEAE-cellulose and Sephadex G-50 chromatography. Homogeneity of the Zn-binding protein was judged by polyacrylamide-disc-gel electrophoresis and gel-permeation chromatography in the presence of 6 M-guanidinium chloride. The molecular weight determined by gel-permeation chromatography was 3900. This value is in good agreement with the minimum molecular weight calculated from the amino acid composition, which was 3655. Zn-binding protein is composed of 36 amino acid residues and the distinctive features include an extremely high content of cysteine, which accounted for one-third of the total amino acid residues, and a complete absence of aromatic amino acids, as well as of methionine, histidine and arginine. Zn-binding protein contained 4.1 g-atoms of zinc per mol and a trace of cadmium, but no copper, iron or calcium. The molar ratio of reactive thiol groups to metal ion was calculated to be 2.73:1. Possible roles of this Zn-binding protein in the homoeostasis of zinc in unfertilized sea-urchin eggs are discussed.

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