Use of the plastein reaction for the modification of cotton-plant proteins

Pronase hydrolysates have been obtained from cottonseed meal which were then used as a substrate for the performance of the plastein reaction. The possibility has been shown of introducing deficient amino acids — lysine methionine, threonine, and tryptophan — by means of this reaction.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 92–96, January–February, 1986.     

Mass spectra of synthesized mixed bromochloroacetic acids

Mass spectra of methyl esters of three common drinking water chlorination by-products, bromodichloroacetic acid, dibromochloroacetic acid and tribromoacetic acid, are presented. The spectra are obtained in electron impact and chemical ionization modes, using a quadrupole mass spectrometer. Proposed fragment ion assignments are presented in detail. Fragment clusters were identified from their m/z values and confirmed with their relative isotope ratios. The detailed mass spectra presented are especially useful because standards for these drinking water contaminants are not yet commercially available.     

Transesterification of mixtures of triglycerides in the presence of cotton-plant lipase

The transesterification of mixtures of cottonseed oil with beef fat in the presence of cotton plant lipase immobilized on a solid support has been studied. A regime for the transesterification of the triglycerides permitting transesterificates suitable for the production of margarine and bakers' and confectioners' articles have been found.A. R. Beruni Tashkent Politechnic Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 439–441, July–August, 1983.     

MFTIR spectra of polyethylene synthesized on germanium surfaces

MFTIR spectra of thin layers of polyethylene synthesized on the surfaces of germanium monocrystals in the 700–3000 cm^–1 range have been investigated. The optical constants of the polymer n() and () have been calculated in the range of natural absorption corresponding to the C-H valence vibration bands. Dichroism of the 2848 and 2912 cm^–1 bands disclosed is caused by the orienting influence of the monocrystal surface and in value is comparable with values obtained for monoaxially oriented massive specimens of polyethylene having a high degree of crystallinity. There have been established reversible changes of the relative orientation function of the macromolecule surface layer during heating and cooling of the specimens in the temperature range 293–355 K. This is explained by the nematic state of the polymer in the thin layer, the macromolecules of which are chemically bonded to the surface of the germanium monocrystal.Deceased.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 24, No. 3, pp. 380–383, May–June, 1988.The authors express their gratitude to K. K. Kalnin'sh for valuable discussion of material in the article and to M. E. Yudovich for his assistance in the calculations.     

Pressure effects on the Raman spectra of proteins: Pressure-induced changes in the conformation of lysozyme in aqueous solutions

The Raman spectrum of pressure-denatured lysozyme in aqueous solution is reported for the first time. Only minor changes occur up to 3.6 kbar. At 5.5 kbar irreversible denaturation and precipitation occurs. The results provide new interpretations for other experimental findings on pressure-induced changes in lysozyme.     

The structure of the xylan from cotton-plant stems

Summary The results of a study of the products of the hydrolysis and oxidative cleavage according to Barry of cotton-plant-stem xylan has shown that its main chain consists of 14--L-anhydroxylopyranose units. Each elementary link of the xylan contains 6–7 xylopyranose units and has two side chains formed by residues of D-glucose and D-glucuronic acid, which are attached in position 2 or 3 of the xylose units of the main chain.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 305–308, May–June, 1973.     

Mass-spectrometric characteristics of the molecular species of cotton-plant phosphatidylcholine

Summary The quantitative identification of the molecular species of phosphatidylcholine in the form of their monoacetyldiglycerides has been performed by a mass-spectrometric method.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 305–307, May–June, 1978.     

Selective dye-labeling of newly synthesized proteins in bacterial cells

We describe fluorescence labeling of newly synthesized proteins in Escherichia coli cells by means of Cu(I)-catalyzed cycloaddition between alkynyl amino acid side chains and the fluorogenic dye 3-azido-7-hydroxycoumarin. The method involves co-translational labeling of proteins by the non-natural amino acids homopropargylglycine (Hpg) or ethynylphenylalanine (Eth) followed by treatment with the dye. As a demonstration, the model protein barstar was expressed and treated overnight with Cu(I) and 3-azido-7-hydroxycoumarin. Examination of treated cells by confocal microscopy revealed that strong fluorescence enhancement was observed only for alkynyl-barstar treated with Cu(I) and the reactive dye. The cellular fluorescence was punctate, and gel electrophoresis confirmed that labeled barstar was localized in inclusion bodies. Other proteins showed little fluorescence. Examination of treated cells by fluorimetry demonstrated that cultures supplemented with Eth or Hpg showed an 8- to 14-fold enhancement in fluorescence intensity after labeling. Addition of a protein synthesis inhibitor reduced the emission intensity to levels slightly above background, confirming selective labeling of newly synthesized proteins in the bacterial cell.     

Change in the structural elements of cotton-plant lignins in the various vegetation periods

Summary 1. The dioxane lignins of the cottonplant of various vegetation periods have been studied, and it has been shown that the lignin changes in the course of the development of the plant: the amount of methoxy groups increases and the amount of phenolic hydroxy groups decreases.2. Gel chromatography of the lignins has shown that they are all polydisperse with a predominance of the high-molecular-weight fraction.3. The 3,4-diethoxybenzaldehyde detected in the products of the alkaline nitrobenzene oxidation of dioxane lignin of the early vegetation period after its ethylation with diethyl sulfate is a direct proof of the presence of catechol structural units in cotton-plant lignin.4. A quantitative determination of the catechol structures in the lignins of the cottonplant has shown that their amount decreases as the plant develops.5. By decomposing the lignins with sodium and liquid ammonia, the presence in them of guaiacyl, syringyl, and p-coumaryl structural units has been confirmed and it has been shown that the lignin becomes less condensed as the plant grows, which is apparently connected with an increase in the degree of its methoxylation.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 100–107, January–February, 1977.     

Influence of additions of anthraquinone on the alkaline hydrolysis of cotton-plant lignin

The action of catalytic amounts of anthraquinone on the alkaline hydrolysis of the stems and dioxane lignin of the cotton plant of the ssp.mexicanium has been investigated. It has been established that this leads to a substantial increase in the yield of low-molecular-weight hydrolysis products. Analysis of the monomeric fractions of the hydrolysis products by the GLC method has shown the presence in them of large amounts of substances with a p-coumaryl structure. This, and also the low level of syringyl derivatives, may be caused by the demethoxylation of the lignin under the conditions described.Institute of the Chemistry of Plant Substances, Academy of Sciences of the USSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 391–395, May–June, 1985.     

Valency changes of sulphur in the mass spectra of sulphones

The aryl substituent has been shown to affect the fragmentation and abundance of skeletal rearrangement ions in the spectra of aryl sulphonyl chlorides and sulphonic acids. The spectra of 2-hydroxy and 2-chloroethyl aryl sulphones contain [aryl SO]⁺ ions, suggesting that alkyl migration has competed successfully with aryl migration to the electron deficient oxygen atom.     

Reductive cleavage by sodium in liquid ammonia of the lignin of cotton-plant stems

Summary 1. The reductive degradation by metallic sodium and liquid ammonia of the lignin of green cotton-plant stems has confirmed the presence in them of three types of structural units: syringyl, guaiacyl, and p-hydroxycoumaryl.2. The preliminary sonication of the plant with ultrasound leads to a decrease in the amount of products containing methoxy groups in the aromatic nucleus, particularly syringyl structures.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 643–646, September–October, 1976.     

Amino acid compositions of proteins synthesized in vitro in the cell nuclei of eukaryotes

The proteins synthesized in vitro by the nuclei of animal and plant cells differ in their amino acid compositions. The differences found show the species specificity of the products. A. S. Sadykov Institute of Bioorganic Chemistry, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 669–671, September–October, 1990.