Isolation and properties of catechol-cleaving yeasts from coir rets

A suitable method for the selective isolation of catechol-cleaving yeasts from coir rets has been worked out. The yeast strains, all belonging toDebaryomyces hansenii, were found to demand biotin as an essential vitamin. The organism has the ability to grow on catechol, phenol and some related compounds as sole source of carbon. It tolerates 0.4% catechol and 0.26% phenol. Evidence was obtained that the catechol-cleaving enzyme of the isolates is a pyrocatechase. Some properties of the cell-free catechol oxygenase are described.

The Isolation and Characterization of β-N-Oxalyl-L-α,β-Diaminopropionic Acid: A Neurotoxin from the Seeds of Lathyrus sativus

A neurotoxic compound has been isolated from the seeds of Lathyrus sativus in 0.5% yield and characterized as β-N-oxalyl-L-α,β-diaminopropionic acid. The compound is highly acidic in character and forms oxalic acid and diaminopropionic acid on acid hydrolysis. The compound has a specific rotation of -36.9° and has apparent pK values in the order of 1.95, 2.95, and 9.25, corresponding to the two carboxyl and one amino functions, respectively. The compound has been synthesized by reacting an aqueous methanolic solution of the copper complex of L-α,β-diaminopropionic acid prepared at pH 4.5-5.0 with dimethyl oxalate under controlled pH conditions and isolating the compound by chromatography on a Dowex 50-H+ column after precipitating the copper. The compound induced severe neurological symptoms in day-old chicks at the level of 20 mg/chick, but not in rats or mice. It also inhibited the growth of several microorganisms and of the insect larva Corcyra cephalonica Staint. L-Homoarginine had no neural action in chicks. It is suggested that the neurotoxic compound is species specific in its action and may be related to "neurolathyrism" associated with the human consumption of L. sativus seeds.

Isolation and partial characterization of sheep plasma α1-mucoprotein

1. 1. Sheep plasma α1-mucoprotein was isolated in an electrophoretically homogeneous state by a combination of ammonium sulphate saturation, isoelectric precipitation and preparative agar electrophoresis in a yield of approx. 150 mg/l of plasma. 2. 2. The mucoprotein was water-soluble, non-coagulable on heating at 100°, not precipitable by 1.8 M perchloric acid, 10% trichloroacetic acid but precipitable by saturated ammonium sulphate solution, 0.6 M sulfosalicylic acid and 5% phosphotungstic acid in 2 N HCl. It had E1 cm1 % value of 9.57 at 278 mμ in water, refractive-index index increment 1.9·10-4 (g/l) in water, isoelectric point at pH 4.45 (sodium acetate-acetic acid buffer) and was homogeneous in pH range 4.0-11.5 but at pH values 2.6 and 3.5 showed some dissociation. 3. 3. The mucoprotein had the following chemical composition: Nitrogen, 12.4%; polypeptide, 77.4%; total hexose (only mannose and galactose), 7.1%; fucose, 1.0%; glucosamine, 4.9% and sialic acid, 4.8%. It had no N-terminal amino acid.

Isolation and characterization of a gonadotropin receptor binding inhibitor from porcine follicular fluid

The presence of a gonadotropin receptor binding inhibitor in pooled porcine follicular fluid has been demonstrated. Porcine follicular fluid fractionation on DE-32 at near neutral pH, followed by a cation exchange chromatography on SPC-50 and Cibacron blue affinity chromatography, yielded a partially purified gonadotropin receptor binding inhibitor (GI-4). The partially purified GI binding inhibitor inhibited the binding of both 125I labelled hFSH and hCG to rat ovarian receptor preparation. SDS electrophoresis of radioiodinated partially purified GI followed by autoradiography made it possible to identify the binding component as a protein of molecular weight of 80000. Subjecting 125I labelled GI-4 to chromatography on Sephadex G-100 helped obtain a homogeneous material, Gl-5. The 125I labelled GI-5 exhibited in its binding to ovarian membrane preparations characteristics typical of a ligand-receptor interaction such as saturability, sensitivity to reaction conditions as time, ligand and receptor concentrations and finally displaceability by unlabelled inhibitor as well as FSH and hCG in a dose dependent manner. This material could bind ovarian receptors for both FSH and LH, its binding being inhibited by added FSH or hCG in a dose dependent manner.

Isoselenocyanates derived from Boc/Z-amino acids: synthesis, isolation,characterization, and application to the efficient synthesis of unsymmetrical selenoureas and selenoureidopeptidomimetics

Isoselenocyanates derived from Boc/Z-amino acids are prepared by the reaction of the corresponding isonitriles with selenium powder in presence of triethylamine at reflux. The utility of these new classes of isoselenocyanates in the preparation of selenoureidodipeptidomimetics possessing both amino as well as carboxy termini has been accomplished. The H-1 NMR analysis confirmed that the protocol involving the conversion of isonitriles to isoselenocyanates and their use as coupling agents in assembling selenour-eido derivatives is free from racemization. (C) 2010 Elsevier Ltd. All rights reserved.

Chemical approaches of penicillin allergy—III Isolation of the penicillin-free carrier receptor protein (CRP) on a polymeric 7-deoxy penicillin analogue template and its role in penicillin immunogeneses in rabbit and man

Specific penicillin-carrier receptor proteins (CRP) have been isolated from the sera of penicillin allergic rabbits and human subjects in the unconjugated native state in electrophoretically homogeneous form by employing a synthetic polymeric affinity template containing the 7-deoxy analogue of penicillin G. The synthesis of the 7-deoxy analogue has been described. In this affinity system the antipenicillin-antibody is desorbed by 0·9M thiourea and the CRP in 8M urea. The CRP after incubation with penicillin is converted into the full-fledged antigen. Studies on the origin of CRP and the nature of antibody as well as comparative studies on the properties of the rabbit antibody and those of antibodies elicited by a BSA-BPO conjugate are reported.

Isolation and characterization of heat-stable allergens from shrimp (Penaeus indicus)

Shrimp are among the more common causes of immediate hypersensitivity reactions to food. To characterize better the allergenic substances within shrimp, extracts from heated shrimp were systematically examined with solid-phase radioimmunoassay and sera from patients clinically sensitive to shrimp. Two heat-stable protein allergens, designated as Sa-I and Sa-II, were identified from boiled shrimp (Penaeus indicus) extracts. Sa-I was isolated by ultrafiltration, Sephadex G-25, and diethylaminoethyl-Sephacel chromatography, whereas Sa-II, the major allergen, was purified by successive chromatography on diethylaminoethyl-Sephacel, Bio-Gel P-200, and Sepharose 4B columns. Sa-I, which was homogeneous by polyacrylamide gel electrophoresis (PAGE), elicited a single band on sodium dodecyl sulfate-PAGE corresponding to a molecular weight of 8.2 kd. Sa-II was also found to be homogeneous by PAGE, crossed immunoelectrophoresis, and immunoblotting. On sodium dodecyl sulfate-PAGE, it elicited a single band with a molecular weight of 34 kd. Sa-II was found to contain 301 amino acid residues and was particularly rich in glutamate/glutamine and aspartate/asparagine. Solid-phase radioimmunoassay-inhibition studies revealed that Sa-I and Sa-II share 54% of the allergenic epitopes, suggesting that Sa-I may be a fragment of Sa-II.SDS-PAGE, Sodium dodecyl sulfate-polyacrylamide gel electrophoresis; MW, Molecular weight; BSA, Bovine serum albumin; DEAE, Diethylaminoethyl; SPRIA, Solid-phase radioimmunoassay; CIE, Crossed immunoelectrophoresis .

Isolation and characterization of a naturally occurring inhibitor from mung bean (Vigna radiata) seedlings for serine hydroxymethyltransferase

A naturally occurring inhibitor of serine hydroxymethyltransferase (EC2.1.2.1) in mung bean seedlings extracts was purified by ammonium sulphate precipitation, phenyl-Sepharose chromatography followed by heating to release the inhibitor bound to the protein. The inhibitor had an absorption maximum at 200 nm, was not precipitated by trichloroacetic acid, was dialysable and resistant to inactivation by heating at 98-degrees-C for 4 hr, protease and ribonuclease digestion; but was acid labile. The chromatographically pure preparation inhibited both mung bean and sheep liver SHMT. Qualitative and quantitative analyses indicated that it contained a carbohydrate moiety, an O-amino and vicinal diol groups. Paper electrophoresis at pH 4.3 suggested that the inhibitor was positively charged.

Isolation and characterization of a novel multibridged tetradentate dianionic form of pyridoxic acid. Crystal structure of tetranuclear [Cu4(PAA)2(Bipyam)4(H2O)2Cl2](NO3)2·CH3OH·10H2O

The X-ray analysis of the tetranuclear copper(II) complex formed from pyridoxic acid and 2,2′-dipyridylamine reveals a novel metal binding mode of pyridoxic acid as a multibridged tetradentate dianion. Here the pyridoxic acid moiety uses all possible sites except the pyridine nitrogen for metal coordination.

Isolation and characterization of thiamin-binding protein from chicken egg white

A thiamin-binding protein was isolated and characterized from chicken egg white by affinity chromatography on thiamin pyrophosphate coupled to aminoethyl-Sepharose. The high specificity of interaction between the thiamin-binding protein and the riboflavin-binding protein of the egg white, with a protein/protein molar ratio of 1.0, led to the development of an alternative procedure that used the riboflavin-binding protein immobilized on CNBr-activated Sepharose as the affinity matrix. The thiamin-binding protein thus isolated was homogeneous by the criteria of polyacrylamide-gel disc electrophoresis, double immunodiffusion and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, had a mol.wt. of 38,000 +/- 2000 and was not a glycoprotein. The protein bound [14C]thiamin was a molar ratio of 1.0, with dissociation constant (Kd) 0.3 micrometer.