Influence of Blood Group and Secretor Status on Carbohydrate Structures in Human Gastric Mucins: Implications for Peptic Ulcer

1995 ◽  
Vol 89 (4) ◽  
pp. 405-415 ◽  
Author(s):  
R. L. Sidebotham ◽  
J. H. Baron ◽  
J. Schrager ◽  
J. Spencer ◽  
J. R. Clamp ◽  
...  
Keyword(s):  
Peptic Ulcer ◽  
Amino Acid ◽  
Blood Group ◽  
Average Length ◽  
Amino Acid Residues ◽  
Secretor Status ◽  
Increased Risk ◽  
The Mean ◽  
The Difference ◽  
Carbohydrate Chains

1. The content and distribution of carbohydrate was examined in mucus glycopolypeptides from human antral mucosae. 2. The mean amount of carbohydrate per 1000 amino acid residues was found to be similar in glycopolypeptides with A, B or H activity. It was slightly, though significantly, less in glycopolypeptides lacking these determinants, because carbohydrate chains were of a shorter average length than in the A-, B- or H-active preparations. This difference was reflected in the sizes of oligosaccharide—alcohols released from representative glycopolypeptides with alkaline borohydride. 3. Differences between A-, B- or H-active and non-secretor glycopolypeptides in terms of the mean number of carbohydrate chains per 1000 amino acid residues were found to be small, and without significance. 4. The average number of peripheral monosaccharide units per 1000 amino acid residues was greater in A-active than in H-active, and least in non-secretor, glycopolypeptides. This order was reversed for monosaccharide units incorporated into skeletal (core plus backbone) structures. The difference in each case was statistically significant. 5. These findings suggest that the increased risk of peptic ulcer associated with blood group O and non-secretor status is unlikely to be attributable to an inherent deficiency in the protective mucus layer, linked to differences between mucins that are associated with A, B or H activity. Other hypotheses linked to infection with Helicobacter pylori are examined.

scholarly journals On the chemical diversity of the prebiotic ocean of early Earth

2014 ◽  
Vol 14 (3) ◽  
pp. 497-504
Author(s):  
Carlo Canepa
Keyword(s):  
Amino Acid ◽  
Average Length ◽  
Chemical Species ◽  
Catalytic Efficiency ◽  
Chemical Diversity ◽  
Aqueous Environment ◽  
Amino Acid Residues ◽  
Catalytically Active ◽  
Order Of Magnitude ◽  
The Mean

AbstractThis work investigates the consequences on the diverse number of chemical species in a pre-biotic terrestrial aqueous environment endowed with an amino acid source induced by the spontaneous build-up of catalytically active polypeptides from amino acid monomers. The assumed probability that a randomly formed polypeptide exhibits catalytic properties is dependent on constraining both the chemical identity and the position of a fraction of the amino acid residues. Within this hypothesis, and using values of the average length n of the catalytic polypeptides about one half of the present-day enzymes, the stationary-state concentration of the catalytically active polypeptides is ≈10−30 −10−19 M, and the ratio of the concentration of a product of a catalytic process to the initial concentration of the corresponding substrate is predicted to be ≈10−6−105. Matching the mean life of each catalytic polypeptide to the mean life of its substrate (λ ≈ ω) is only possible by significantly raising the intensity of the source of the amino acid monomers. Under these hypothetical optimal conditions, the mean lives of the catalytic polypeptides and their substrates have values ω−1 ≈ λ−1 ≈10 yr and the asymptotic concentration of each product is of the same order of magnitude as the concentration of the substrate. In all cases the catalytic efficiency necessary to form the active peptides takes the typical values of present-day enzymes.

scholarly journals Phenylalanine requirement in children with classical PKU determined by indicator amino acid oxidation

2002 ◽  
Vol 283 (6) ◽  
pp. E1249-E1256 ◽  
Author(s):  
Glenda Courtney-Martin ◽  
Rachelle Bross ◽  
Mahroukh Raffi ◽  
Joe T. R. Clarke ◽  
Ronald O. Ball ◽  
...  
Keyword(s):  
Amino Acid ◽  
Acid Oxidation ◽  
Phenylalanine Concentration ◽  
Two Phase ◽  
Amino Acid Oxidation ◽  
Blood Phenylalanine ◽  
Plasma Phenylalanine ◽  
Crossover Analysis ◽  
The Mean ◽  
The Difference

Dietary restriction of phenylalanine is the main treatment for phenylketonuria (PKU), and current estimates of requirements are based on plasma phenylalanine concentration and growth. The present study aimed to determine more precisely the phenylalanine requirements in patients with the disease by use of indicator amino acid oxidation, withl-[1-13C]lysine as the indicator. Breath13CO2 production (F13 co 2) was used as the end point. Finger-prick blood samples were also collected for measurement of phenylalanine to relate phenylalanine intake to blood phenylalanine levels. The mean phenylalanine requirement, estimated using a two-phase linear regression crossover analysis, was 14 mg · kg−1 · day−1, and the safe population intake (upper 95% confidence interval of the mean) was found to be 19.5 mg · kg−1 · day−1. A balance between phenylalanine intake and the difference between fed and fasted blood phenylalanine concentration was observed at an intake of 20 mg · kg−1 · day−1. The similarity between these two values (19.5 and 20 mg · kg−1 · day−1) suggests that the maximal phenylalanine intake for children with PKU should be no higher than 20 mg · kg−1 · day−1.

scholarly journals Anti-M monoclonal antibodies cross-reacting with variant Mg antigen: an example of modulation of antigenic properties of peptide by its glycosylation

Blood ◽  
1994 ◽  
Vol 84 (7) ◽  
pp. 2340-2345 ◽  
Author(s):  
E Jaskiewicz ◽  
M Czerwinski ◽  
D Syper ◽  
E Lisowska
Keyword(s):  
Monoclonal Antibodies ◽  
Amino Acid ◽  
Blood Group ◽  
Polypeptide Chain ◽  
Protein Glycosylation ◽  
Glycophorin A ◽  
Amino Acid Residues ◽  
Terminal Portion ◽  
Peptide Analogs ◽  
Antigenic Properties

Abstract Some monoclonal antibodies (MoAbs) directed against blood group M- related epitope of glycophorin A (GPA) were found to agglutinate rare variant erythrocytes carrying GPA of Mg type. In contradistinction to normal GPA-M or -N, the N-terminal portion of GPA-Mg is not glycosylated. Therefore, the multipin peptide synthesis was used for testing the specificity of the cross-reacting MoAbs. Among several anti- M and anti-N MoAbs tested, only three anti-M (E3, E6, 425/2B) agglutinated Mg erythrocytes and showed binding to the synthetic octapeptides corresponding to N-terminal sequences of GPA-M (SSTTGVAM), GPA-N (LSTTEVAM), and GPA-Mg (LSTNEVAM). Testing multiple peptide analogs (window and replacement analysis) showed that these MoAbs were specific for peptidic epitope in which Met8 and Val6 were the most essential amino acid residues. The amino acid replacements Ser<-->Leu1 or Gly<-->Glu5 (M v N) and Thr<-->Asn4 (M and N v Mg) had no or negligible effect on the reaction of synthetic peptides with the MoAbs. However, when Ser2, Thr3, and Thr4 carry O-linked sialooligosaccharides (normal GPA-M or -N), the MoAbs recognize Gly5- and sialic acid- dependent blood group M-related epitope. An interesting finding concerning anti-M/Mg MoAbs described here is the fact that glycosylation of amino acid residues adjacent to the most important part of peptidic epitope not only differentially modulates the proper exposure of peptidic epitope, but also alters the requirement for some amino acid residues present within the epitope. Pathologic conditions, including hematologic disorders, are often accompanied by alterations in protein glycosylation, resulting not only from differences in the structure of antigen polypeptide chain, but also from changes in specificity or expression of enzymes involved in glycosylation. Our present findings draw attention to possibility of the bidirectional modulation of protein antigenicity by glycosylation and may be helpful in interpretation of some results obtained with MoAb used for diagnostic or other purposes.

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.

Changes to Mucins in Uninvolved Mucosa and at the Tumour Site in Gastric Adenocarcinoma of Intestinal Type

1998 ◽  
Vol 94 (1) ◽  
pp. 87-99
Author(s):  
R. L. Sidebotham ◽  
N. K. Dhir ◽  
J. B. Elder ◽  
J. Spencer ◽  
M. M. Walker ◽  
...  
Keyword(s):  
Amino Acid ◽  
Gastric Mucosa ◽  
Carbohydrate Chain ◽  
Intestinal Type ◽  
Amino Acid Residues ◽  
Mucous Cells ◽  
Tumour Site ◽  
Mucin Histochemistry ◽  
Gastric Type ◽  
Carbohydrate Chains

1. Mucin histochemistry is markedly altered in the stomach in intestinal-type adenocarcinoma. To increase understanding of these changes we have examined the content and distribution of carbohydrate in mucus glycopolypeptides isolated from non-malignant antrum, and from the uninvolved gastric mucosa and tumour site of patients with this disease. 2. The content of carbohydrate declined by 12.6% (P = 0.02) in mucus glycopolypeptides from uninvolved gastric mucosa when compared with those from non-malignant antrum, and by a further 25.4% (P < 0.001) in mucus glycopolypeptides from the tumour site. The first of these changes was accompanied by a significant decrease in the number of carbohydrate chains/1000 amino acid residues, and a significant increase in the number of monosaccharide units in each carbohydrate chain. The second of these changes was accompanied by significant decreases in both the number of carbohydrate chains/1000 amino acid residues, and in the number of monosaccharide units in each carbohydrate chain. 3. The number of sulphated monosaccharide units/100 carbohydrate chains increased from a mean of 7.2 in mucus glycopolypeptides from non-malignant antrum to a mean of 27.2 (P < 0.001) in preparations from uninvolved gastric mucosa and 22.7 (P < 0.001) in preparations from the tumour site. 4. Evidence is presented that these structural changes to mucus glycopolypeptides from the malignant stomach are due to an abnormal mucin biosynthesis by metaplastic goblet cells and/or immature gastric-type mucous cells within the uninvolved mucosa, and immature mucous cells at the tumour site.

scholarly journals Determination of three amino acids causing alteration of proteolytic activities of staphylococcal glutamyl endopeptidases

2009 ◽  
Vol 390 (3) ◽  
Author(s):  
Takayuki K. Nemoto ◽  
Toshio Ono ◽  
Yu Shimoyama ◽  
Shigenobu Kimura ◽  
Yuko Ohara-Nemoto
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protease Activity ◽  
Binding Pocket ◽  
Catalytic Triad ◽  
Amino Acid Residues ◽  
Proteolytic Activities ◽  
Hydrophobic Amino Acids ◽  
The Difference

Abstract Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus warneri secrete glutamyl endopeptidases, designated GluV8, GluSE, and GluSW, respectively. The order of their protease activities is GluSE<GluSW<<GluV8. In the present study, we investigated the mechanism that causes these differences. Expression of chimeric proteins between GluV8 and GluSE revealed that the difference is primarily attributed to amino acid residues 170–195, which define the intrinsic protease activity, and additionally to residues 119–169, which affect the proteolytic sensitivity. Among nine substitutions present in residues 170–195 of the three proteases, the substitutions at positions 185, 188, and 189 were responsible for the changes in their activities, and the combination of W185, V188, and P189, which naturally occurs in GluV8, exerts the highest protease activity. W185 and P189 were indispensable for full activity, but V188 could be replaced by hydrophobic amino acids. These three amino acid residues appear to create a substrate-binding pocket together with the catalytic triad and the N-terminal V1, and therefore define the K m values of the proteases. We also describe a method to produce a chimeric form of GluSE and GluV8 that is resistant to proteolysis, and therefore possesses 4-fold higher activity than the wild-type recombinant GluV8.

scholarly journals Association between secretor status and Lewis phenotype with seronegative spondyloarthritis as indicator of autoimmunity

Genetika ◽  
2020 ◽  
Vol 52 (1) ◽  
pp. 127-136
Author(s):  
Ivan Busarcevic ◽  
Svetlana Vojvodic ◽  
Una Vojvodic
Keyword(s):  
Blood Group ◽  
Haemagglutination Inhibition ◽  
Gastrointestinal Symptoms ◽  
Blood Group Antigens ◽  
Control Subjects ◽  
Secretor Status ◽  
Lewis Blood Group ◽  
Increased Risk ◽  
Significant Difference ◽  
Seronegative Spondyloarthropathies

The classical paradigm of autoimmune pathogenesis involving specific genetic makeup and exposure to environmental triggers has been challenged recently by the addition of a third element, the loss of intestinal barrier function. Regardless of HLA B27 phenotype or gastrointestinal symptoms, evidence of ileitis, ileocolitis or colitis exists in patients with spondyloarthropathy. The FUT2 secretory gene is a strong candidate for Crohn's susceptibility by shaping the functional states of mucosal microbiota and may thus have influence on the release of zonulin, the main regulator of gut permeability. Gram negative bacteria precipitate and may be involved in the pathogenesis of spondyloarthropathies. Susceptibility to many infectious agents is associated with ABO blood group or secretor state. Patients who cannot secrete ABO and Lewis blood group antigens into body fluids, an ability controlled by a single gene on chromosome 19, are known to be at increased risk of certain autoimmune diseases associated with human leukocyte antigen (HLA) markers. Lewis (Le) blood group phenotype can be used to infer secretor status. The objective of this study was to determine the distribution of secretor state and Lewis blood group phenotype in patients with seronegative spondyloarthropathies and healthy control subjects. Hundred and ten (110) patients with seronegative spondyloarthropathies (58 females and 52 males) and 103 control (74 males and 29 females) subjects participated in this study. Samples of saliva and blood were subjected to haemagglutination inhibition tests for determination of secretor status and Lewis phenotype. A total of 92(84%) patients and 92 (89%) control subjects were secretors while 18 (16%) patients and 11 (11%) control subjects were non-secretors. There was no statistically significant difference (?2 1,461 p<0,05 and degrees of freedom 1) in distribution of secretor status in comparison to seronegative spondyloarthropathies by comparing two observed populations. Seven patients had modified (reduced) expression of Lewis b antigen on their erythrocytes. Reduction of Lewis b antigen expression was not observed on erythrocytes of healthy subjects. Reduced expression of Lewis b antigen could be a consequence of the inflammatory process within the gut and it also suggests several pathogenic mechanisms which may be relevant to the synthesis of Lewis antigens inside the gut or its absorption on erythrocytes in patients with spondyloarthropathy.

scholarly journals The Acinetobacter baylyi hfq Gene Encodes a Large Protein with an Unusual C Terminus

2009 ◽  
Vol 191 (17) ◽  
pp. 5553-5562 ◽  
Author(s):  
Dominik Schilling ◽  
Ulrike Gerischer
Keyword(s):  
Amino Acid ◽  
Gene Localization ◽  
Amino Acid Residues ◽  
Acinetobacter Baylyi ◽  
Reading Frame ◽  
Rich Domain ◽  
C Terminus ◽  
The Difference ◽  
Cell Phenotypes

ABSTRACT In gammaproteobacteria the Hfq protein shows a great variation in size, especially in its C-terminal part. Extremely large Hfq proteins consisting of almost 200 amino acid residues and more are found within the gammaproteobacterial family Moraxellaceae. The difference in size compared to other Hfq proteins is due to a glycine-rich domain near the C-terminal end of the protein. Acinetobacter baylyi, a nonpathogenic soil bacterium and member of the Moraxellaceae encodes a large 174-amino-acid Hfq homologue containing the unique and repetitive amino acid pattern GGGFGGQ within the glycine-rich domain. Despite the presence of the C-terminal extension, A. baylyi Hfq complemented an Escherichia coli hfq mutant in vivo. By using polyclonal anti-Hfq antibodies, we detected the large A. baylyi Hfq that corresponds to its annotated size indicating the expression and stability of the full protein. Deletion of the complete A. baylyi hfq open reading frame resulted in severe reduction of growth. In addition, a deletion or overexpression of Hfq was accompanied by the loss of cell chain assembly. The glycine-rich domain was not responsible for growth and cell phenotypes. hfq gene localization in A. baylyi is strictly conserved within the mutL-miaA-hfq operon, and we show that hfq expression starts within the preceding miaA gene or further upstream.

scholarly journals Bremazocine Recognizes the Difference in Four Amino Acid Residues to Discriminate Between a Nociceptin/Orphanin FQ Receptor and Opioid Receptors

1998 ◽  
Vol 77 (4) ◽  
pp. 301-306 ◽  
Author(s):  
Takahiro Seki ◽  
Masabumi Minami ◽  
Chiaki Kimura ◽  
Tomoya Uehara ◽  
Takayuki Nakagawa ◽  
...  
Keyword(s):  
Amino Acid ◽  
Opioid Receptors ◽  
Amino Acid Residues ◽  
Orphanin Fq ◽  
The Difference
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