S. Bricteux-Grégoire

Phylogeny of trypsinogen activation peptides

Abstract 1. 1. Trypsinogen has been isolated and purified from several artiodactyls, including the sheep, the goat, the wild boar, the red deer, the roe deer and the dromedary. 2. 2. The activation peptides have been identified and their sequence determined. 3. 3. The sequence of all known trypsinogen activation peptides have been compared. These sequences allow the tracing back of some of the possible mutations which have affected the N-terminalpart of trypsinogen during the past 70 million years.

Les constituants osmotiquement actifs des muscles et leur contribution a la regulation isosmotique intracellulaire chez Limulus polyphemus

Resume 1. 1. The chemical composition of the blood and of the intracellular medium of the muscles has been studied in the king crab ( Limulus polyphemus ) and compared with that of marine decapods (Crustaceans) and of a scorpion, Androctonus australis . 2. 2. The blood of Limulus contains only very small amounts of free amino acids. The amino-acid composition of the muscles of Limulus differs from that of decapods, but is similar to that of the scorpion, with respect to its lower concentration and to the relative proportions of free arginine and free glycine. 3. 3. The intracellular osmolar effectors in Limulus are principally dialysable nitrogenous compounds, other than amino acids and taurine. These unidentified substances play an important role in the isosmotic intracellular regulation which takes place when Limulus is adapted to brackish water (40% sea water). This is another difference between Limulus and marine decapods; the latter show a regulation in which free amino acids are among the most important effectors.

Prism conchiolin of modern or fossil molluscan shells. An empire of protein paleization

Abstract 1. 1. While global nacre conchiolin shows in its composition the predominantly concentrations of four amino acids: glycine, alanine, serine and aspartic acid, global prism conchiolin shows a different pattern, characterized by two predominantly amino acids: glycine and aspartic acid. 2. 2. Prism conchiolin has been isolated from fossil shells of Pinna affinis (London, Clay, Lower Eocene) and Inoceramus sp. (Gault, Cretaceous). The comparison of modern and fossil prism conchiolins shows differences in the pattern of amino acid composition. The significance of these differences is discussed.

N-terminal amino acid sequence of dromedary trypsinogen.

Abstract The sequence of the activation peptide of dromedary trypsinogen has been determined and compared with that of other artiodactyls and of one perissodactyl and two primitive fishes.

Composition chimique du tube d'un pogonophore (Siboglinum SP.) et des formations squelettiques de deux pterobranches

Abstract The chemical composition of the skeletons of two species of pterobranchs, Cephalodiscus inaequatus (Andersson) and Rhabdopleura sp. and of one pogonophore, Siboglinum sp., was studied quantitatively. The tubes of Siboglinum sp. are composed of proteins (about 47 %) and chitin (about 33 %); these two substances are probably associated in large amounts as glycoproteic complexes. The amino acid composition suggests that these proteins belong to the class of scleroproteins. Their composition is very different from that of collagen and keratin. On the contrary, the coenecium of the two pterobranchs does not contain any chitin and the amounts of proteins are much lower (19 %). The proteins are characterized by a very high proportion of glycine (35 % of the total amount of amino acids).

Purification, propriétés et séquence N-terminale du trypsinogène de chèvre

Goat trypsinogen has been extracted with acid from goat pancreas and purified by two chromatographies on CM-cellulose. Its purity has been checked by ultracentrifugation and polyacrylamide gel electrophoresis. Its amino acid composition is only slightly different from that of sheep trypsinogen, but its isoelectric point must be lower Two N-terminal residues, phenylalanine and valine, have been detected. Semiquantitative results indicate that phenylalanine and valine are in the ratio of 4 Phe to 1 Val. Two activation peptides are split during the activation: the hexapeptide Val-Asp-Asp-Asp-Asp-Lys and the octapeptide Phe-Pro-Val-Asp-Asp-Asp-Asp-Lys. The same activation peptides have been found in sheep, red deer and roe deer trysinogens. We conclude to the existence of two trypsinogens, one of them lacking the first two residues Phe-Pro-. However, the production of the latter by the splitting of a Pro-Val bond, occurring either in situ, or during acid extraction, cannot be excluded. The sequence -Asp-Asp-Asp-Asp-Lys is common to all known trypsinogen activation peptides, including ox, sheep, goat, red deer, roe deer, pig, wild boar, horse and dogfish.

N-terminal amino acid sequence of trypsinogen from the lesser rorqual, Balaenoptera acutorostrata (Cetacea). Simultaneous isolation of trypsinogen, chymotrypsinogen and ribonuclease from pancreas.

Abstract Ribonuclease, trypsinogen and two chymotrypsinogens have been extracted from a pancreas of a whale. The activation peptide of trypsinogen has been isolated and its sequence compared with other known sequences. The relative position of the Cetacea among the orders of Mammalia is discussed. A sequence is proposed for the common ancestor of the mammals considered.

N-terminal amino acid sequence of trypsinogen from the elephant seal Mirounga leonina L. (Carnivora)☆

Abstract Trypsinogen has been extracted and purified from the pancreas of an elephant seal. The activation peptide has been isolated and its sequence compared with 13 other known sequences, including those from two primitive fishes and an insect.

Some properties of the interstrand crosslinks in depurinated DNA

The interstrand crosslinks that appear in stored depurinated DNA interfere with the counting of apurinic sites and strand breaks by sucrose gradient analysis. They could not be cleaved at acid or alkaline pH, or by treatment with methoxyamine.

Contributions à la biochimie du ver à soie. XXX. Biosynthèse de tréhalose et de glycogène à partir de glucose-1-phosphate

Abstract 1. 1. When injected into silkworms in the middle of the fifth larval instar, labelled G-1-P is principally used for the synthesis of hemolymph trehalose. 2. 2. Glycogen synthesis from the same source in the fat body proceeds more rapidly in undernourished larvae than in those fed normally. 3. 3. Owing to the poor incorporation of the radioactivity in the glycogen and especially in the trehalose of the fat body, it is suggested that the trehalose could be synthesized from pyruvate elsewhere than in the fat body, and that the biosynthetic pathway of trehalose from pyruvate does not necessarily pass through glycogen. 4. 4. The synthesis of trehalose and glycogen, as well as the hydrolysis of glycogen, could be controlled, directly or indirectly, by the variations of the trehalose level in the hemolymph. 5. 5. The gluconeogenetic pathways in the silkworm are discussed and presented in the form of a partially hypothetical figure.