scholarly journals Polymeric structure of pig small-intestinal mucus glycoprotein. Dissociation by proteolysis or by reduction of disulphide bridges

1981 ◽  
Vol 195 (1) ◽  
pp. 277-285 ◽  
Author(s):  
M Mantle ◽  
D Mantle ◽  
A Allen
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Protein Molecule ◽  
Amino Acid Residues ◽  
Proteolytic Digestion ◽  
Gastric Mucus ◽  
Polymeric Structure ◽  
Mucus Glycoprotein ◽  
Intestinal Mucus ◽  
Small Intestinal

Pig small-intestinal mucus glycoprotein, of molecular weight 1.72 X 10(6), is cleaved by Pronase digestion into glycoprotein subunits of molecular weight 4.5 X 10(5). Of the protein component of the native glycoprotein 29% by weight was lost on Pronase digestion, with no loss of carbohydrate. The non-glycosylated region of the protein that was lost with proteolytic digestion had a broad spectrum of amino acid residues, in contrast with the glycosylated region of the protein, which was resistant to proteolysis and was rich in serine, threonine and proline residues. Reduction with 0.2M-mercaptoethanol dissociated the Pronase-digested glycoprotein subunits into smaller glycoprotein subunits of molecular weight 2.7 X 10(5). On reduction, the native glycoprotein was dissociated into subunits of molecular weight 2.4 X 10(5), a similar size to those obtained from reduction of the Pronase-digested glycoprotein. On reductive dissociation of the native glycoprotein, in addition to glycoprotein subunits, protein was also released principally as a component of 90000 molecular weight. This protein was separated quantitatively from the reduced glycoprotein in amounts compatible with one 90000-mol.wt. protein molecule per 1.72 X 10(6)-mol.wt. native glycoprotein molecule. No 90000-mol.wt. protein was released on reduction of the isolated Pronase-digested glycoprotein. Pig small-intestinal mucus glycoprotein is therefore a covalent polymer of glycoprotein subunits joined by disulphide bridges. This polymeric structure differs in important respects from that previously shown for gastric mucus, in particular with respect to the size and number of component subunits per native molecule.

scholarly journals Characterization of gastric mucoproteins isolated by equilibrium density-gradient centrifugation in caesium chloride

1974 ◽  
Vol 141 (3) ◽  
pp. 633-639 ◽  
Author(s):  
Bryan J. Starkey ◽  
David Snary ◽  
Adrian Allen
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Gradient Centrifugation ◽  
Gel Filtration ◽  
Equilibrium Density ◽  
Amino Acid Residues ◽  
Gastric Mucus ◽  
Terminal Amino Acid ◽  
Terminal Amino

1. The mucoprotein from pig gastric mucus has been purified by equilibrium centrifugation in a CsCl gradient. 2. This procedure removes the non-covalently bound protein, which is closely associated with the mucoprotein and not easily removed from it by gel filtration. 3. The purified mucoprotein is separable by gel filtration into a high-molecular-weight mucoprotein A (mol.wt. 2.3×106) and a low-molecular-weight mucoprotein B/C (mol.wt. 1.15×106). 4. These two mucoproteins have the same chemical analysis namely fucose 11.3%, galactose 26%, glucosamine 19.5%, galactosamine 8.3% and protein 13.6%. 5. Mucoprotein A contains 3.1% ester sulphate. 6. These mucoproteins are isolated without enzymic digestion and have a higher protein content than the blood-group-substance mucoproteins from proteolytic digestion of gastric mucus. Detailed amino acid analysis shows that the extra protein in the non-enzymically digested material is composed of amino acids other than serine and threonine. 7. Mucoproteins A and B/C contain respectively 130 and 9 half-cystine residues per molecule of which about 78 and 6 residues are involved in disulphide linkages. 8. Cleavage of these disulphide linkages by mercaptoethanol splits both mucoproteins into four equally sized subunits of mol.wt. 5.2×105for mucoprotein A and 2.8×104for mucoprotein B/C. 9. The sole N-terminal amino acid of mucoprotein A is aspartic acid, whereas mucoprotein B/C has several different N-terminal amino acid residues.

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.

Studies on Chymotrypsin-P. I. Characterization

1971 ◽  
Vol 49 (9) ◽  
pp. 999-1004 ◽  
Author(s):  
M. C. Shaw ◽  
T. Viswanatha
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Physicochemical Properties ◽  
Gel Filtration ◽  
Amino Acid Residues ◽  
The Difference ◽  
Filtration Technique

The physicochemical properties of chymotrypsin-P obtained by the papain activation of chymotrypsinogen have been investigated. The molecular weight of this enzyme as determined by gel filtration technique has been found to be 24 000 ± 1000. The amino acid residues occupying the N-terminal positions and the composition of the B- and C-chains of chymotrypsin-P are identical with those found in α-chymotrypsin. Thus the difference between the two enzymes is restricted to the composition of their A-chains.

Isolation of Two Bovine Amelogenin Peptides and Their Amino Acid Sequences

1987 ◽  
Vol 1 (2) ◽  
pp. 276-281 ◽  
Author(s):  
J.-H. Yeh ◽  
T. Takagi ◽  
S. Sasaki
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Amino Acid Sequences ◽  
Polyacrylamide Gel ◽  
The Other ◽  
Edman Degradation ◽  
Amino Acid Residues ◽  
Peptide Fractions

Two peptide fractions of bovine amelogenin having a highly aggregative property to form polymers were purified by chromatography, SDS-polyacrylamide gel electrophoresis, and HPLC. Amino acid sequences of purified peptides were determined by automated Edman degradation. One peptide was found to be composed of 63 amino acid residues having a molecular weight of 7105, and the other of 86 residues having that of 9683. The sequence of the smaller peptide was identical to the C-terminal 63 residues of the amelogenin molecule of 170 residues previously reported, but the larger contained eight residues which are absent in the amelogenin sequence. There is a possibility that the latter peptide might be synthesized independently from mRNA spliced at different positions.

Lipids associated with rat small-intestinal mucus glycoprotein

1983 ◽  
Vol 120 ◽  
pp. 67-76 ◽  
Author(s):  
Henryk Witas ◽  
Jerzy Sarosiek ◽  
Mitsuru Aono ◽  
Varahabhotla L.N. Murty ◽  
Amalia Slomiany ◽  
...  
Keyword(s):  
Mucus Glycoprotein ◽  
Intestinal Mucus ◽  
Small Intestinal

Characterization of the sulfated glycopeptide of chicken pepsinogen

1982 ◽  
Vol 47 (2) ◽  
pp. 709-718 ◽  
Author(s):  
Miroslav Baudyš ◽  
Vladimír Kostka ◽  
Karel Grüner ◽  
Jan Pohl
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Protein Molecule ◽  
Amino Acid Residues ◽  
Terminal Sequence ◽  
Sugar Moiety ◽  
Pepsinogen A ◽  
Identical Amino Acid Sequence ◽  
High Voltage Electrophoresis

S-sulfonated chicken pepsinogen was digested with TPCK-trypsin; large tryptic peptides, separated on Sephadex G-25 fine, were subjected to additional cleavage with α-chymotrypsin. The hold-up fraction of the chymotryptic digest from the Sephadex G-25 column, was resolved by high voltage electrophoresis. The three most acidic zones contained glycopeptides of identical amino acid sequence Val-Ser-Thr-Asn-Glu-Thr-Val-Tyr, yet differed in the composition of the sugar moiety. These glycopeptides, moreover, bear different numbers of sulfate groups which enabled the resolution of the peptides. The most acidic glycopeptide contains 7 glucosamine residues, 3 mannose residues and 5 sulfate groups, the second one 6 glucosamine residues, 3 mannose residues and 4 sulfate groups and the slowest, minority glycopeptide, 5 glucosamine residues, 2 mannose residues and 2 sulfate groups. The entire sugar moiety is attached to one of the chain viaasparagine. In other experiments the glycopeptides were also isolated from the thermolytic digest of chicken pepsin; their C-terminal sequence was shorter by two amino acid residues. The tentative assignment of the glycopeptides to the amino acid sequence of pepsinogen resulted from the analysis of the limited tryptic digest of the whole protein molecule. Chicken pepsinogen is glycosylated at the site of the chain occupied by a phosphoserine residue in hog pepsinogen A.

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