BTCI enhances guanylin-induced natriuresis and promotes renal glomerular and tubular effects.

Guanylin and uroguanylin are small cysteine-rich peptides involved in the regulation of fluid and electrolyte homeostasis through binding and activation of guanylyl cyclases signaling molecules expressed in intestine and kidney. Guanylin is less potent than uroguanylin as a natriuretic agent and is degraded in vitro by chymotrypsin due to unique structural features in the bioactive moiety of the peptide. Thus, the aim of this study was to verify whether or not guanylin is degraded by chymotrypsin-like proteases present in the kidney brush-border membranes.

Ontogenetic variation of metalloproteinases and plasma coagulant activity in venoms of wild Bothrops atrox specimens from Amazonian rain forest.

A comparative study of venoms from juvenile, sub-adult and adult wild Bothrops atrox specimens captured in Manaus region (Brazil) was performed. All venoms tested had acidic pH (5.5) and the human plasma coagulant activity was higher in venoms from juvenile and sub-adult specimens than in adults.

[Pharmacological effects of arginine supplementation in rats with Walker 256 solid tumor].

The effects of diet arginine supplementation for those with cancer are controversial. We evaluate the effects of dietetic supplementation with arginine over body weight, growth of tumor, metastatic dissemination, surviving time, amino acid metabolism, haematological changes of the rats with Walker 256 solid tumor. Intragastrical solutions with arginine at 4% and 6%, a standard diet (control) were administered to the animals.

Amino acid sequence of a myotoxic Lys49-phospholipase A2 homologue from the venom of Cerrophidion (Bothrops) godmani.

The complete amino acid sequence of myotoxin II (godMT-II), a myotoxic phospholipase A2 (PLA2) homologue from the venom of the Central American crotaline snake Cerrophidion (Bothrops) godmani, was determined by direct protein sequencing methods. GodMT-II is a class II PLA2 showing a Lys instead of Asp at position 49. An additional substitution in the calcium binding loop region (Asn instead of Tyr at position 28) suggests the lack of enzymatic activity observed in this toxin is due to loss of its ability to bind the co-factor Ca2+, since the residues involved in forming the catalytic network of PLA2s (His-48, Tyr-52 and Asp-99) are conserved in godMT-II.

Improving the recovery of lysine in automated protein sequencing.

Automated protein sequencing is an important tool in protein characterization. Most instruments use tetrahydrofuran (THF) as the HPLC eluent for separation of the derivatized amino acids residues. THF is highly perishable when exposed to air, generating peroxides which can degrade amino acids, mainly lysine, leading to uncertainty in chromatogram interpretations.

Determination of the amino acid sequence of the plant cytolysin enterolobin.

The cytolytic seed protein enterolobin from seeds of Enterolobium contortisiliquum was purified by using FPLC on a Mono Q column giving a single peak in capillary electrophoresis. The complete amino acid sequence of the plant cytolysin was determined by an automated method, yielding a molecular mass of 54,806 Da. Databank searches and sequence alignment demonstrated a high degree of sequence identity and similarity between enterolobin and bacterial aerolysins from Aeromonas hydrophila and A.

Amino acid sequence of the Phaseolus vulgaris var. "fogo na serra" inhibitor and interactive surface modeling for the enzyme-inhibitor complex.

A trypsin and chymotrypsin inhibitor from seeds of Phaseolus vulgaris var. "Fogo na Serra" (PFSI) was purified and its complete amino acid sequence was determined using Edman degradation methods. The inhibitor was found to belong to the Bowman-Birk family of enzymatic inhibitors; it has 82 amino acid residues and a 8.

Compared chemical properties of dermonecrotic and lethal toxins from spiders of the genus Loxosceles (Araneae).

Loxosceles spider venom usually causes a typical dermonecrotic lesion in bitten patients, but it may also cause systemic effects that may be lethal. Gel filtration on Sephadex G-100 of Loxosceles gaucho, L. laeta, or L.

Purification, characterization, sequence determination, and mass spectrometric analysis of a trypsin inhibitor from seeds of the Brazilian tree Dipteryx alata (Leguminosae).

Dipteryx alata trypsin inhibitor (DATI) has been purified and completely sequenced. It showed homology to members of the Bowman-Birk family of inhibitors. The last step of DATI purification by RP-HPLC (narrow-borc C18 column) suggested the existence of some isoforms of the inhibitor due to the presence of a cluster of very close peaks in the chromatogram.

Amino acid sequence and disulphide-bridge pattern of three gamma-thionins from Sorghum bicolor.

The complete primary structure of a new alpha-amylase inhibitor from Sorghum bicolor belonging to the gamma-thionin family has been determined and the amino acid sequences of two components of the family already elucidated have been corrected by combining the classical Edman degradation with advanced mass spectrometric procedures. The same integrated approach allowed us to define the pattern of the disulphide bridges in the three isoinhibitors. The arrangement of the cysteine pairing was determined as Cys3-Cys47, Cys14-Cys34, Cys20-Cys41 and Cys24-Cys43.

Homology between the seed cytolysin enterolobin and bacterial aerolysins.

Enterolobin, a 55-kDa cytolytic, inflammatory, and insecticidal protein isolated from seeds of the Brazilian tree Enterolobium contortisiliquum (Leguminosae-Mimosoideae) has been further purified and partially sequenced by using both manual and automated methods. A computational search of enterolobin partial amino acid sequence against the PIR database revealed possible sequence similarities with aerolysins, cytolytic proteins from Aeromonas species. An alignment of enterolobin partial sequence to the amino acid sequences of A.

Enterolobin induces rat paw oedema independently of PAF-acether.

The potential participation of PAF-acether (PAF) on the paw oedema triggered by enterolobin was investigated. Intraplantar injections of enterolobin (5-20 micrograms/paw) yielded a dose response curve for oedema which appeared after 30 min, peaked in the interval between 2-4 h and faded after 24 h. The pre-treatment with BN 52021, but not with other PAF antagonists such as PCA 4248 or WEB 2086, significantly blocked enterolobin-induced oedema.

Pro-inflammatory activity of enterolobin: a haemolytic protein purified from seeds of the Brazilian tree Enterolobium contortisiliquum.

The pro-inflammatory activity of enterolobin, a haemolytic protein from Enterolobium contortisiliquum seeds, was investigated. In doses ranging from 1 to 20 micrograms/site, enterolobin induced a dose-dependent paw oedema and pleurisy in rats. The effect was apparent after 15 min, peaked at 6 hr and decreased 24 hr after enterolobin was administered.

Enterolobin, a hemolytic protein from Enterolobium contortisiliquum seeds (Leguminosae--Mimosoideae). Purification and characterization.

Hemolytic and phospholipase D activities were found in the saline extract of Enterolobium contortisiliquum seeds. The hemolytic activity is due to a protein which was named enterolobin. This protein was highly purified by extraction with 0.

The complete amino acid sequence of the Vigna unguiculata (L.) Walp. seed trypsin and chymotrypsin inhibitor.

The amino acid sequence of the "double-headed" trypsin and chymotrypsin inhibitor (BTCI), purified from the cowpea Vigna unguiculata (L.) Walp. cv "Seridó" was determined in our laboratory.

The presence of histamine in Cnidosculus oligandrus (Euphorbiaceae).

1) The presence of histamine in prickles and lead and stem tissues of Cnidosculus oligandrus (Mull. Arg) Pax & Hoffm (Euphorbiaceae) is reported. 2) Prickles on stems and leaves have larger amounts of histamine, as determined by the isolated guinea-pig ileum and by fluorimetry of the condensation product of the histamine and ortho-phthalaldehyde (OPT).