Primary structure of the alanine subunit of ricin T from seeds of the Central Asian castor oil plant. V. Peptides obtained by cyanogen bromide cleavage

The cleavage of the carboxymethylated Ala subunit of ricin T by cyanogen bromide has been performed. Four fragments have been isolated in the individual state by gel filtration and high-voltage paper electrophoresis. The sequence of the cyanogen bromide peptides in the protein chain has been established. Partial structures of three cyanogen bromide fragments have been determined.     

Chemical characterization of the crystalline proteins ofBac. thuringiensis. Cleavage with cyanogen bromide

The crystalline proteins fromBac. thuringiensis of the third and fourth serotypes with a molecular weight of 130,000 have been isolated and carboxymethylated, and their amino acid compositions has been determined. The CM-proteins have been found to be labile in acid media (80% CF₃COOH and 65% HCOOH). Conditions have been found for the cleavage of the CM-protein of the third serotype with cyanogen bromide. A BrCN fragment with a molecular weight of 16,000 has been isolated, the intensity of which in 5% polyacrylamide gel on scanning amounts to about half the intensity of the sum of all the fragments. The aminoacid composition of this fragment has been determined.Institute of Chemistry of the Bashkir Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 384–386, May–June, 1980.     

Primary structure of triacetinase — An esterase from cotton seeds IV. Peptides of the chymotryptic and thermolytic hydrolysis of cyanogen bromide fragments of triacetinase

Summary 1. Peptides from a chymotryptic hydrolyzate of cyanogen bromide fragment B-7 have been isolated and characterized. The structure of some peptides of the chymotryptic hydrolyzate have been studied and this has enabled the tryptic peptides to be linked up.2. The peptides of a thermolysin hydrolyzate of cyanogen bromide B-5 have been isolated and characterized. The study of the structure of the thermolysin peptides has permitted the linking of two tryptic peptides.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 248–253, March–April, 1978.     

Use of disk electrophoresis for the separation of large peptide fragments of proteins

Summary The disk electrophoresis of peptide fragments from porcine pepsin obtained by cleaving the pepsin with cyanogen bromide has been performed. A method has been developed for extracting the colored peptide fractions after electrophoresis in polyacrylamide gel. An amino-acid analysis has been performed of peptide fragments B1, B2, and B4 isolated by disk electrophoresis. The results obtained have been compared with the amino-acid composition calculated from the structures of these peptides. The possibility has been shown of using the method described during structural investigations of both proteins and their low-molecular-weight fragments.The peptide preparations were supplied to us by I. Surova, V. Ostoslavskaya, L. Revina, I. Puracheva, É. Vakhitova, and G. Muratova. The amino-acid analysis was performed by E. Timokhina, A. Balduev, G. Fedyukina, O. Khodova, and N. Ivashechkina.All-Union Scientific-Research Institute of the Genetics and Breeding of Industrial Microorganisms. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 219–222, March–April, 1975.     

A study of the structure of lactosomatotropic hormone

Summary 1. Peptides from tryptic hydrolysis of the cyanogen bromide fragments B-1 and B-2 of LSTH have been isolated and characterized.2. The differences found in the amino-acid sequence of the individual peptides of fragment B of LSTH as compared with the corresponding sections of the O-LTH molecule are not due to species differences of the hormones.All-Union Scientific-Research Institute of the Technology of Blood Substitutes and Hormone Preparations. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 502–507, July–August, 1975.     

Primary structure of subunit B of the 11S globulin of cotton seeds of variety 108-F. IV. High-molecular-weight peptides from the complete tryptic hydrolysis and from tryptic hydrolysis at the arginine residues of subunit B

The high-molecular-weight peptides from the complete tryptic hydrolysis and tryptic hydrolysis at arginine residues of subunit B, which contained uncleaved bonds of the basic amino acids, have been studied. In the investigation of these peptides, use was made of additional cleavage by trypsin at lysine residues and of cyanogen bromide cleavage.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 227–230, March–April, 1984.     

Primary structure of triacetinase — An esterase from cotton seeds III. Peptides from tryptic hydrolysis

Summary 1. The peptides from tryptic hydrolysis of triacetinase have been isolated and characterized and their amino-acid sequences have been determined.2. On the basis of the results of the determination of the amino-acid sequences of the peptides of the tryptic hydrolyzate the sequence of peptides of the cyanogen bromide hydrolysis of triacetinase has been established or confirmed.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 241–248, March–April, 1978.     

Cleavage of the peptide bonds in pepsin with cyanogen bromide

Summary 1. Conditions for the cyanogen bromide cleavage of the peptide bonds of pepsin formed by methionine have been found.2. Pepsin contains a methionyl-valine bond and two methionyl-aspartic acid (or methionyl-asparagine) bonds.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 2, pp. 138–141, 1966     

Investigation of the pyrolysis products of methionine-enkephalin-Arg-Gly-Leu using liquid chromatography-tandem mass spectrometry

Low-temperature pyrolysis of methionine-enkephalin-Arg-Gly-Leu has been carried out and the non-volatile residues have been analyzed. The fragments were separated and characterized by LC-UV/Vis-MS/MS. Two major types of pyrolysis products were identified by matching the experimental results with a theoretical list that contains the expected fragments. These products were mainly composed of cyclic oligopeptides and linear fragments produced from the peptide backbone. These fragments have preserved the sequence of amino acids in the peptide. In some cases, a complete or partial loss of an amino-acid side group was observed. Tandem mass spectrometry and cyanogen bromide cleavage experiments were used to confirm the nature of the cyclic and linear pyrolysates, in addition to chromatographic and mass spectrometric data of actual standard synthetic cyclic peptides.     

Primary structure of the alanine subunit of ricin T from the seeds of the Central Asian castor oil plant VI. Tryptic peptides of the cyanogen bromide fragments B-1, B-2, and B-3

Tryptic hydrolysates of cyanogen bromide fragments B-1, B-2, and B-3 have been studied. As a results, 23 tryptic peptides have been isolated and characterized and the primary structures of 22 of them have been established. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 801–806, November–December, 1998.     

Condensed thiolane 1,1-dioxide system

Alkylation of trans-N-alkyl(or aryl)-N'-(3-hydroxy-1,1-dioxothiolan-4-yl) thioureas with ethyl p-toluenesulfonate, and the reaction of cyanogen bromide wiht an ethyl p-toluenesulfonate, and the reaction of cyanogen bromide with trans-3-hydroxy-4-aminothiolan-1,1-dioxides have given salts of trans-2-iminoperhydrothieno[3,4-d]-oxazole 5,5-dioxides. Rearrangement of these oxazolidines in the presence of bases afford perhydrothieno[3,4-d]imidazole-2-one 5,5-dioxides.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 268–271, February, 1988.     

Über die existenz und theorie der elektromeren formen des chlorcyans : Ein beitrag zur theorie der jodometrischen bromidbestimmung über bromcyan

It has been observed that in E. Schulek's method for the iodometric determination of bromide via BrCN, ClCN is formed depending on the temperature and the pH. The yellow colour of the latter, and also its ability to oxidize iodide, disappear after a short while. Reaction-kinetic experiments have shown that the formation of yellow cyanogen chloride and its reaction with iodide ion is to be considered as a monomolecular collision reaction. Yellow cyanogen chloride represents the hitherto not observable “electromeric” form of CICN in which the chlorine has a certain amount of positive charge (Cl+O-CN).     

Semisynthesis iii - the homoserine 12,105 analogue of hen egg-white lysozyme.

The homoserine ^12,105 analogue of Hen egg-white lysozyme has been prepared by two routes. In the first approach a large excess of cyanogen bromide was used to cleave the native enzyme at methionines 12 and 105, the tertiary structure being maintained by the presence of the four disulphide bonds. Formation of the two new amide bonds was achieved using the activation of the homoserine lactone residues generated at positions 12 and 105; the reaction being most efficient when anhydrous DMSO was used as the solvent. An alternative approach using limited (two-fold excess) cyanogen bromide digestion gave the same homoserine analogue without chain fragmentation. A purified sample of the analogue showed no enzymic activity.     

Purification and determination of the binding site of lactate dehydrogenase from chicken breast muscle on immobilized ferric ions.

Lactate dehydrogenase from chicken breast muscle was purified to homogeneity in one step by immobilized metal ion affinity chromatography. The purified enzyme was used to localize the binding site to immobilized Fe(III) ions. After cyanogen bromide degradation and digestion with trypsin, small enzyme fragments capable of binding to immobilized Fe(III) ions were obtained. It is proposed that several histidyl groups are involved in the binding.     

Condensed 1,3-benzothiazinones. 1. Facile synthesis of 2-amino-1,2,4-triazolo[5,1-b][1,3]-benzothiazin-9-one

Treating 2-mercaptobenzohydrazide ( 1a ) with cyanogen bromide gave 3-amino-2-imino-3,4-dihydro-2.H-1,3-benzothiazin-4-one ( 2a ). This compound underwent further cyclocondensation with a second molecule of cyanogen bromide or S-methylisothiourea sulfate to afford the biologically interesting 2-amino-1,2,4-triazolo-[5,1-b][1,3]benzothiazin-9-one ( 3c ). Compound 3c could also be prepared directly from 1a by treating with excess amount of cyanogen bromide in more satisfactory yield.     

Synthesis of an adsorbed reversed-phase packing material for the separation of proteins and peptides

We have described the preparation and chromatographic evaluation of an adsorbed hydrophobic stationary phase suitable for reversed-phase chromatography of proteins and peptides. The synthetic procedure involves three steps: the adsorption of a polyamine to the silica surface; crosslinking of the adsorbed polyamine layer with a bis-phenyl difunctional epoxide; and the benzoylation of the remaining accessible amino groups. Performance of this chromatographic material compared favorably with SynChropak RP-8 silica (SynChrom, Linden, IN, U.S.A.) and was stable to 40% formic acid. Good separations were obtained between the components of sample mixtures containing proteins or the cyanogen bromide fragments of sperm whale myoglobin. However, in both cases, the adsorbed hydrophobic stationary phase was less retentive. Furthermore, this medium exhibited slightly different selectivity. Whereas the heme which was present in the cyanogen bromide digest of myoglobin desorbed as the second peak from the RP-8 column, it eluted last from the adsorbed stationary phase. Comparable performance, acid stability and alternate selectivity suggest that this material is an interesting alternative to organosilane reversed-phase coatings.     

Gold bromide complexes in acidic aqueous solutions from 25° to 300°C. A laser raman spectroscopic study

Raman spectra of gold bromide complexes in acidic solutions (pH=–0.3–3) have been recorded at 25° to 300°C and at pressures on the liquid vapor curve for the system. At 25°C, only the square planar Au(III) bromide complex, AuBr ₄ ^– , is present in solution with bands at approximately 105, 197 and 215 cm^–1. However, in these acidic solutions, when the temperature is 50°C or higher, the square planar Au(III) bromide complex is partially transformed into the linear Au(I) bromide complex, AuBr ₂ ^– , with a single band near 208 cm^–1. The transformation of the Au(III) square planar tetrabromo complex into the Au(I) linear dibromo complex is also favored by a reduction of the oxygen fugacity and an increase in pH.     

Nitrogenous heterocycles. 6. Reactions of organomagnesium derivatives of 7-aza- and benzoindoles with diethyl oxalate and the reactivity of ethoxalylindoles

The reactions of organomagnesium derivatives of 2-methyl- or 2,3-dimethyl-7-azaindoles and 2,3-dimethylbenz[4,5]- or -[6,7]indoles with diethyl oxalate, and the reactivity of the resulting ethoxalylindoles towards phenylmagnesium bromide, have been examined. It has been shown that the course of the reaction is dependent on the solvent and the structures of the starting materials.No footnote given in Russian original — Publisher.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1206–1209, September, 1987.     

Osmotic Coefficients and Activity Coefficients of Nonaqueous Electrolyte Solutions. Part 3. Tetraalkylammonium Bromides in Ethanol and 2-Propanol

Vapor pressure lowering by the addition of tetraethylammonium bromide (0.04 to 2.3 m), tetrapropylammonium bromide (0.04–2.7 m), tetrabutylammonium bromide (0.05–2.5 m), bispiperidinium bromide (0.04–0.7 m) to ethanol and tetrapropylammonium bromide (0.04–1.3 m) and tetrabutylammonium bromide (0.03–1.9 m) to 2-propanol was measured at 25°C with high precision. The experimental data of the corresponding osmotic coefficients are compared to those obtained by the use of Pitzer equations and chemical model calculations. Mean activity coefficients are derived from the osmotic coefficients.     

Colorimetric determination of sinalbin

Summary Sinalbin (Sinapinp-hydroxybenzylglucosinolate) is present in white mustard seed(sinapis alba) and on enzymatic hydrolysis liberates a sharp, hot, pungent and flavoury compound,p-hydroxybenzyl isothiocyanate (p-HBI). A new sensitive colorimetric method has been developed in which thep-HBI is reacted with sodium hydroxide to givep-hydroxybenzyl alcohol and sodium thiocyanate. The thiocyanate is converted into cyanogen bromide by reacting it with bromine. The cyanogen bromide is then treated with pyridine—benzidine reagent to give a red colour which has an absorption maximum at 518 nm. The red complex solution obeys Beer's law over the concentration range 0.1–0.5 g of SCN per ml of the solution. One mole of sinalbin gives rise to one mole of thiocyanate ion. Recovery is 90%.

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Zusammenfassung Sinalbin (Sinapin-p-hydroxybenzylglucosinolat) ist ein Inhaltsstoff des Samens von weißem Senf (Sinapis alba) und bildet bei enzymatischer Hydrolyse eine scharf schmeckende, würzig riechende Verbindung, p-Hydroxybenzyl-isothiocyanat (p-HBI). Ein neues kolorimetrisches Verfahren wurde entwickelt, das auf der Reaktion von p-HBI mit Natronlauge beruht, wobei p-Hydroxybenzylalkohol und NaCNS entstehen. Dieses wird mit Brom zu Bromcyan umgesetzt, das seinerseits mit Pyridin-Benzidin eine Rotfärbung mit dem Absorptionsmaximum bei 518 nm gibt. Die Lösung dieser roten Komplexverbindung folgt dem Beer'schen Gesetz von 0,1–0,5 g SCN^–/ml. Ein Mol Sinalbin entspricht einem Grammion Thiocyanat. Die Ausbeute beträgt etwa 90%.