Hull-less Barley Varieties: Storage Proteins and Amino Acid Distribution in Relation to Nutritional Quality

Barley (Hordeum vulgare L.) has had an important impact on human nutrition. Hull-less barley is a genetically improved type that has been widely used in recent years. Six Brazilian hull-less barley varieties (IAC-IBON 214-82; IAC 8612-421; IAC 8501-31; IAC 8501-12; IAPAR 39-ACUMAI; IAC 8501-22) were analyzed for storage protein constituents, amino acid contents, and similarity among the hull-less barley varieties. Albumins, globulins, prolamins I and II, and glutelins were extracted and separated by SDS-PAGE. The total protein amino acid contents of the flour were also determined for each variety by TLC and HPLC. Variations in intensity and appearance and disappearance of protein bands were observed among the varieties suggesting genetic variability. However, the amino acid profile did not indicate any major variations in the amino acid concentrations. The high lysine and threonine total concentrations detected in the seeds of the hull-less barley varieties encouraged an investigation into the regulation of amino acid metabolism and storage protein synthesis.     

Saccharopine Dehydrogenase Activity in the High-Lysine Opaque and Floury Maize Mutants

Lysine is an essential amino acid normally present in very low concentration in cereal seeds. In previous reports we have studied the metabolism of lysine in several distinct high-lysine maize mutants and observed drastic variations in the activity of saccharopine dehydrogenase (SDH), a key enzyme involved in lysine degradation. We have now analyzed the activity of SDH using non-denaturing polyacrylamide gel electrophoresis (PAGE) to identify possible isoenzymes that could explain the patterns of activity previously observed. The results indicated the presence of at least two SDH isoenzymes, one contributing to approximately 90% of the total enzyme activity and a minor form only present in the wild type lines and the opaque-1 mutant. The results suggest that the differences in total SDH activity among the genotypes tested are due to alterations in the predominant SDH isoenzymic form, which is likely to be the bifunctional polypeptide containing lysine 2-oxoglutarate reductase.     

赖氨酸与谷氨酰胺在谷氨酰胺转胺酶作用下的交联反应

本文研究了赖氨酸与谷氨酰胺在谷氨酰胺转胺酶催化下的交联反应。探讨了底物比、加酶量、pH值、反应温度和反应时间对聚合度的影响。利用Design-Expert6.0.3软件优化得出交联反应的最佳工艺条件为底物比2.15、加酶量14.39U/g、pH值8.0、温度42℃和反应时间94min。同时,分析了各因素之间的交互效应。     

Hull-less Barley Varieties: Storage Proteins and Amino Acid Distribution in Relation to Nutritional Quality

Abstract

Barley (Hordeum vulgare L.) has had an important impact on human nutrition. Hull-less barley is a genetically improved type that has been widely used in recent years. Six Brazilian hull-less barley varieties (IAC-IBON 214-82; IAC 8612-421; IAC 8501-31; IAC 8501-12; IAPAR 39-ACUMAI; IAC 8501-22) were analyzed for storage protein constituents, amino acid contents, and similarity among the hull-less barley varieties. Albumins, globulins, prolamins I and II, and glutelins were extracted and separated by SDS-PAGE. The total protein amino acid contents of the flour were also determined for each variety by TLC and HPLC. Variations in intensity and appearance and disappearance of protein bands were observed among the varieties suggesting genetic variability. However, the amino acid profile did not indicate any major variations in the amino acid concentrations. The high lysine and threonine total concentrations detected in the seeds of the hull-less barley varieties encouraged an investigation into the regulation of amino acid metabolism and storage protein synthesis.     

Comparative analysis of polyspecificity of the endogenous tRNA synthetase of different expression host towards photocrosslinking amino acids using an in silico approach

Photo-induced covalent crosslinking has emerged as the powerful strategy for analyzing and characterizing the protein–protein interaction and mapping protein 3D conformations. In the last decades, a number of photocrosslinking amino acids have been reported but only a few have been efficiently utilized for photocrosslinking purposes. Recently, incorporation of diazirine containing photoactivatable analogs such as photo-methionine, photo-leucine, photo-isoleucine and photo-lysine into target proteins were accomplished in live cells (Human A549cells, HEK 293) by depleting corresponding natural amino acid and supplementing these analogs in the medium. Likewise, incorporation of photo-methionine and photo-leucine is also reported in E. coli. Incorporation of these unnatural amino acids were demonstrated only in a limited number species, thereby conventional methods have been utilized for the protein–protein interaction study in other species. With this in mind, we studied in silico analysis of polyspecificity of four endogenous tRNA synthetases (LeuRS, IleRS, MetRS, and LysRS) from six different species such as Escherichia coli, Pseudomonas fluorescens, Corynebacterium glutamicum, Saccharomyces cerevisiae, Aspergillus oryzae and Homo sapiens towards its photocrosslinking amino acids. In addition, here we describe the active site similarity of different protein bio-factories. Based on the active site similarity and similar binding mode, we predicted that the endogenous tRNA synthetases of all the species are reactive to corresponding photoactivatable analogs. This is the first in silico study to demonstrate that the photocrosslinking unnatural amino acids are recognized by the endogenous tRNA synthetases of different protein expression biofactories.     

Effect of Drying Conditions and Level of Condensed Distillers Solubles on Protein Quality of Wheat Distillers Dried Grain with Solubles

Reduced protein quality is one of the concerns currently confronting the supply and utilization of wheat distillers dried grain with solubles (DDGS) as an animal feed ingredient. This study assessed the protein quality of wheat DDGS, expressed as acid detergent insoluble crude protein (ADICP) and lysine content, by blending wet distillers grain (WDG) with varying condensed distillers solubles (CDS) levels and drying using forced air convection, microwave, and microwave–convection methods. As the CDS level was increased, the protein content of wheat DDGS generated from the three drying methods increased. Interactions of CDS level with drying air temperature, microwave power, and microwave–convection settings had a significant effect (p < 0.05) on average ADICP and lysine contents. Higher ADICP and lower lysine contents were observed in samples dried at higher temperature, microwave power, and microwave convection settings. Further, the CDS level significantly affected the color parameters of microwave- and microwave–convection-dried samples and the drying air temperature–CDS level interaction significantly affected the color of forced air convection–dried samples. Significant lysine content–redness, ADICP–lightness color parameter, and ADICP–total color difference correlations were found in forced air convection–, microwave-, and microwave–convection-dried samples, respectively. Microwave and microwave–convection drying achieved desirable protein quality associated with low-temperature drying at much shorter times.     

Application of lysine, taurine, disodium inosinate and disodium guanylate in fermented cooked sausages with 50% replacement of NaCl by KCl

The effects of 50% replacement of NaCl by KCl and addition of the amino acids lysine and taurine and the 5'-ribonucleotide disodium inosinate and disodium guanylate on some sensory and physicochemical parameters of fermented cooked sausages were evaluated. The partial replacement of NaCl by KCl did not alter the manufacturing process; however, defects in the sensory quality were detected. Lysine at a concentration of 0.313% and a mixture of taurine (750 mg/kg) with disodium inosinate (300 mg/kg) and disodium guanylate (300 mg/kg) reduced the sensory defects caused by KCl, allowing the fermented cooked sausages to be elaborated with reduced sodium content and high sensory quality.     

Synthesis and characterization of biodegradable non-toxic poly(ester-urethane-urea)s based on poly(ε-caprolactone) and amino acid derivatives

Non-toxic biodegradable linear poly(ester-urethane-urea)s with different hydrophilic character were synthesized from poly(ε-caprolactone) as macrodiol, l-lysine diisocyanate (LDI) and ethyl ester l-lysine or l-ornithine as chain extenders. Linear segmented polymers were synthesized by the prepolymer method with a tertiary amine playing a critical role in the chain extension in heterogeneous conditions. The prepared segmented polymers were fully chemically and physically characterized, including water uptake and hydrolytic stability measurements. Depending on the poly(ε-caprolactone) length, the segmented polymers were amorphous or semicrystalline. The crystallinity degree strongly affected the mechanical properties and water uptake behaviour.     

Correlations between some nitrogen fractions,lysine, histidine,tyrosine, and ornithine contents during the germination of peas,beans, and lentils

The effect of different germination conditions, namely, germination time and total presence or absence of light, on the content of the various nitrogen fractions, three essential protein amino acids (Lys, His, and Tyr) and one non-protein amino acid (Orn), was studied in peas, beans, and lentils. The influence of light during germination on the parameters considered varied according to the legume but on the whole was less important than the influence of germination time in quantitative terms. In all three legumes, prolonging the germination time yielded flours that contained more non-protein nitrogen (NPN) and Orn and less protein nitrogen (PN) and Lys, while the changes in the His and Tyr contents varied with legume type. In addition, changes in the Lys, Tyr, and Orn contents correlated with the changes in the NPN and PN levels in the germinated legumes.