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C Richet

Publications and source records attributed to C Richet.

At least 37 records · Page 2Linked to original sources
PubMed1986

The major human urinary trypsin inhibitor is a proteoglycan.

The major urinary trypsin inhibitor (Mr 44 000), isolated from human urine, contains 35% carbohydrate. In addition to N-acetylglucosamine and neutral sugars (primarily mannose and galactose), the carbohydrate moiety contains hexuronic acid and N-acetylgalactosamine and corresponds to a glycosaminoglycan. This carbohydrate chain is an integral component of the inhibitor: it does not dissociate from the inhibitor when using dissociative conditions such as sodium dodecyl sulfate, guanidinium chloride, or by increasing ionic strength or mixing with cetylpyridinium chloride. This glycosaminoglycan chain is sensitive to chondroitinase ABC or testicular hyaluronidase digestion and corresponds to slightly sulfated chondroitin 4-sulfate or 6-sulfate. After treatment by these enzymes, the urinary inhibitor has a lower molecular mass (Mr 26 000) but still inhibits trypsin.

Amino Acids↗
PubMed1986

Physical and immunological analysis of the two domains isolated from a variant surface glycoprotein of Trypanosoma brucei.

A specific surface glycoprotein of a variant of Trypanosoma brucei was cleaved with trypsin and the two major domains of the molecule have been purified. We have studied the chemical composition of each domain and compared the data to published results of the specific cDNA sequence. Circular dichroism measurements show that the amino-terminal domain includes preferentially alpha-helical or beta-sheet structure. The physicochemical analyses are supplemented by a prediction of secondary structure and a statistical pattern of hydrophilicity-hydrophobicity. The results are discussed in light of the internal limits that were described in the process of partial gene conversion occurring between the variant gene sequence and related members of the same gene family. Immunoblots with homologous antiserum indicate that the amino-terminal domain is implicated in antigenicity. In addition, immunoblotting with heterologous antiserum on native antigen, tryptic hydrolysates, or purified domains suggests a site of interaction supported by the two domains.

Animals↗
PubMed1986

[Horizontal cubito-radial pinning in fractures of the distal radius including a postero-internal fragment].

The authors describe 68 articular fractures of the lower end of the radius in which a postero-medial accessory fragment was displaced. They have made a study of the anatomy and fibrous connections of the fragment and conclude that this fragment is best maintained reduced by a transverse pin passed from the ulna towards the radius. They attach great importance in such fractures to injury to the triangular radio-ulnar ligament and to inferior radio-ulnar dislocation.

Adult↗
PubMed1985

Trypanosoma brucei: the extent of conversion in antigen genes may be related to the DNA coding specificity.

The boundaries of gene conversion in variant-specific antigen genes have been determined in six clones of Trypanosoma brucei. In each clone, antigenic switching involved interaction between two telomeric members of the AnTat 1.1 multigene family, which share extensive homology throughout their coding regions. All conversion events occurred by substitution of faithful copies of donor sequences. Conversion endpoints were nonrandomly distributed. In four clones, the 5' conversion limit was near the antigen translation initiation codon, while in three clones, the 3' conversion limit was located at the "hinge" between the two major antigen domains. In one case, two segmental conversions were involved in antigen switching. These observations reveal that antigen gene conversion can occur without generating point mutations, and suggest that postrecombinational selection may impose a limit on the number of possible rearrangements within antigen genes.

Amino Acid Sequence↗
PubMed1983

Presence of glycerol and fatty acids in the C-terminal end of a variant surface glycoprotein from Trypanosoma equiperdum.

The composition of the C-terminal end of a variant surface glycoprotein from Trypanosoma equiperdum (BoTat-1 VSG) has been examined. It has been reported for two Trypanosoma brucei VSGs (Holder, A.A., Biochem. J. (1983), 209, 261-262) that ethanolamine was involved in binding the C-terminal amino acid to an oligosaccharide side chain. Tryptic glycopeptides were prepared from BoTat-1 VSG and analyzed. One of them was found to contain ethanolamine and consequently was assumed to be C-terminal. It was shown that the glycopeptide also included phosphate, glycerol and fatty acids. The fatty acid composition was representative of that of glycerolipids. All the results suggest that the end of the molecule is a core of phosphatidylethanolamine.

Amino Acids↗
PubMed1983

The variant surface glycoproteins of Trypanosoma equiperdum. Identification of a phosphorylated glycopeptide as the cross-reacting antigenic determinant.

The cross-reacting antigenic determinant in the variant surface glycoproteins (VSGs) of Trypanosoma equiperdum was studied by testing the ability of VSG glycopeptides to bind heterologous anti-VSG sera. VSG glycopeptide purification revealed the presence of 3 oligosaccharide sidechains on the mature VSG. These consist of two sidechains containing only mannose and glucosamine and a third containing galactose and mannose (in a 5:1 ratio) as well as phosphorous and ethanolamine. This phosphorylated fragment completely blocked the binding of VSG to heterologous anti-VSG and therefore contained the cross-reacting determinants.

Animals↗
PubMed1983

Possible amino acid repetitive sequences in the proline-rich glycoprotein of human parotid saliva.

The amino acid sequence of the proline-rich glycoprotein from human parotid saliva was studied using different preparations: native glycoprotein, tryptic glycopeptides, and their chemically deglycosylated homologous derivatives. The results indicate very similar structural features of the proline-rich glycoprotein and the tryptic glycopeptides and suggest that the peptide backbone of the glycoprotein comprises several repetitive domains containing one carbohydrate-peptide linkage and a proline-rich sequence. These data are in fair agreement with a preceding circular dichroism study (Aubert, J.P., Porchet, N., Boersma, A., Loucheux-Lefevbre, M.H. and Degand, P. (1982) Biochim. Biophys. Acta 704, 361-365).

Amino Acid Sequence↗
PubMed1983

Variant specific surface antigens from Trypanosoma equiperdum: chemical and physical studies.

Nine variant specific surface antigens were purified from clones of Trypanosoma equiperdum and characterized by amino acid analysis, isoelectric focusing and circular dichroism. The molecules showed extensive differences in their isoelectric points, and by comparison with the corresponding amino acid compositions, this variation seemed to be due to different amide contents. Circular dichroism data allowed one to divide the molecules into 4 groups according to their respective percentages in alpha-helical and beta-sheet structure.

Amino Acids↗
PubMed1983

Partial determination of the primary structure of a variant surface glycoprotein from Trypanosoma equiperdum. Composition and location of a carbohydrate moiety.

Salivarian trypanosomes have the ability to evade the immune response of their hosts by the sequential expression of different cell surface glycoproteins. Among the isolated specific antigens from cloned variants of Trypanosoma equiperdum, a structural study was undertaken on two immunologically cross-reacting variant surface glycoproteins, and results concerning the basic antigenic type are reported. The glycoprotein was cleaved by cyanogen bromide, and amino acids of several purified fractions obtained by gel filtration chromatography of this cleavage mixture were sequenced by automated Edman degradation. Sequencing in particular allowed the identification of the N-terminal portion of the molecule (residues 1-74). Sugar compositions of the fractions have demonstrated the presence of at least two carbohydrate moieties in the glycoprotein. Using a subsequent enzymatic subcleavage we were able to locate the first glycosylation site in position 57. An important observation was that the first oligosaccharide identified was rich in mannose and devoid of galactose.

Amino Acid Sequence↗
PubMed1982

Amino-acid sequence of an alpha-parvalbumin, pI = 4.88, from frog skeletal muscle.

The primary structure of the most basic (pI = 4.88) of the two major parvalbumins from frog skeletal muscle (Rana esculenta) has been determined by partial automatic sequencing of the protein which exhibits a free N terminus, and a study of overlapping peptides obtained by cyanogen bromide cleavage and digestion with trypsin, thermolysin and Armillaria mellea protease. This protein shows the typical structure of an alpha-parvalbumin. Comparison of the primary structure of ion-binding loops of alpha and beta-parvalbumins does not provide a clear-cut explanation of their differences in ion-binding properties.

Agaricales↗
PubMed1977

[Rheological properties of human bronchial secretions: demonstration of proline-rich polypeptides and their role (author's transl)].

Human bronchial secretions were examined for chemical components and rheological properties. Proline-rich polypeptides (PRP) obtained by ultrasonic treatment and by contact with a cationic resin (AG 50WX2) were purified by gel-filtration chromatography and high-voltage electrophoresis. The chemical composition of these components allowed a classification according to their proline, glycine, glutamic acid and lysine contents. Rheological experiments suggest a biological role for the PRP in the fibrillar structure of sputum.

Amino Acids↗