Claudine Paul

Complete amino acid sequence of the Mu heavy chain of a human IgM immunoglobulin

The amino acid sequence of the �, chain of a human IgM immunoglobulin, including the location of all disulfide bridges and oligosaccharides, has been determined. The homology of the constant regions of immunoglobulin �, γ, α, and ε heavy chains reveals evolutionary relationships and suggests that two genes code for each heavy chain.

Revisiting the enzymes stored in the laticifers of Carica papaya in the context of their possible participation in the plant defence mechanism.

Abstract. In the tropical species Carica papaya, the articulated and anastomosing laticifers form a dense network of vessels displayed in all aerial parts of the plant. Damaging the papaya tree inevitably severs its laticifers, eliciting an abrupt release of latex. Besides the well-known cysteine proteinases, papain, chymopapain, caricain and glycyl endopeptidase, papaya latex is also a rich source of other enzymes. Together, these enzymes could provide an important contribution to plant defence mechanisms by sanitising and sealing the wounded areas on the tree.

Oxygen affinity of avian hemoglobins

Abstract 1. 1. Blood from different avian species displays the presence of either two major hemoglobin components, type 1 and type 2, or a unique one similar to type 2. 2. 2. Some aspects of oxygen equilibrium are reported for both types of hemoglobin obtained from several species, namely oxygen affinity in the absence or presence of inositolhexaphosphate, the Bohr effect and the heme-heme interaction. 3. 3. The analogies and differences illustrated at the level of the physicochemical parameters are also observed at the level of the physiological properties.

Macroglobulin Structure: Variable Sequence of Light and Heavy Chains

The variable regions of the light and heavy chains on the same macroglobulin (immunoglobulin M) molecule are no more related in amino acid sequence than are the variable regions of the light and heavy chains of different immunoglobulin molecules. Subgroups of � chains are similar in their variable sequence to subgroups of γ chains.

Reversible modification of thiol-containing polypeptides with poly (ethylene glycol) through formation of mixed disulfide bonds. The case of papaya proteinase III.

Papaya proteinase III (PPIII) was purified, as the S-methylthio derivative from the latex ofCarica papaya L., by ion-exchange chromatography. Separation of reactivable PPIII from the irreversibly oxidized molecular species of this enzyme was readily achieved after a selective conversion of the reactivated proteinase into the S-monomethoxypoly-(ethylene glycol) thio derivative (S-mPEG thio PPIII). From this derivative, a PPIII preparation titrating 1 mol of thiol/mol of enzyme was regenerated. From the physicochemical properties of S-mPEG thio PPIII that were investigated, it is concluded that interactions between the mPEG and the PPIII chains occur only to a limited extent. In addition to its usefulness for purifying thiol-containing enzymes, the mPEG modification resulting from mixed disulfide bond formation may find other practical applications.

The primary sequence of chicken myoglobin (Gallus gallus)

After enzymatic digestion of chicken myoglobin by trypsin, chymotrypsin or thermolysin, the separation of peptides was performed by column chromatography on various ion exchange resins. Each peptide was purified by high-voltage paper electrophoresis or by chromatography either on paper or on ion-exchange resin, and its complete amino acid sequence was then determined by the combined dansyl-Edman procedure and by endopeptidase digestions. The whole globin was submitted to automatic Edman degradation using the Beckman sequencer. Residues have been positioned from overlaps of sequence data between tryptic (T), chymotryptic (C) and thermolysin (Th) peptides. The stepwise degradation of the whole globin confirmed the alignment of the N-terminal third of the molecule. The combination of these different approaches has led to the complete determination of the 153 residues sequence forming the polypeptide chain of chicken myoglobin. Comparison of the established chicken myoglobin structure with those from other species shows a conservation of structure, although the avian protein exhibits more variations in its amino acid sequence than has been found between other known myoglobins which all belong to mammalian species.

Structure of the Hinge Region of the Mu Heavy Chain of Human IgM Immunoglobulins

The amino acid sequence around the central disulfide bridge linking the mu heavy chains of the human immunoglobulin M monomer is unlike that in immunoglobulin G. This hinge area contains one of the five oligosaccharides of the mu chain, is low in proline, and is the site of tryptic cleavage to yield Fab� and Fc� fragments.

Variation and Homology in the Mu and Gamma Heavy Chains of Human Immunoglobulins

Sequence analysis of an 1gM immunoglobulin shows that the variable regions of hunman � and γ1 heavy chainis may have twice as much homology as their constant regions and that evolutionary divergence of � and γ1 heavy chain genes occurred not long after the separation of heavy and light chain genes.

Evaluation of the polyethylene glycol–KF–water system in the context of purifying PEG–protein adducts

Abstract Covalent binding of PEG to proteins leads to conjugates widely investigated in several biotechnological processes. Their use as pharmaceuticals requires both careful purification and proper characterization. In this context, this paper examines the potentialities offered by hydrophobic interaction chromatography and compares aqueous potassium fluoride and ammonium sulfate as the eluents. Relative contribution of the various forces which dictate the chromatographic behaviour of PEG–protein adducts on Fractogel TSK–Butyl 650 is discussed.

Preparation and characterization of a S-monomethoxypoly-(ethylene glycol) thioderivative of papain

Abstract A derivative of papain in which the free thiol group of the proteinase is attached to a poly(ethylene glycol) chain via a disulphide bond has been prepared. The poly(ethylene glycol) chain confers to the conjugate new physico-chemical properties, including a looser binding to ion exchange chromatographic supports such as CM-Sephadex C-50. The conjugate is thus readily separated from the irreversibly oxidized (unconjugated) forms of the enzyme. A papain preparation titrating 0.97 mol of thiol per mol of enzyme is obtained from the conjugate.