Relationship between gliadin peptide structure and their effect on the fetal chick duodenum

The tendency to form a beta-turn in alpha-gliadin was estimated using the B-cell determinant prediction program based on the Chou and Fasman probability of beta-turn formation. Six sequences possessing a high probability of beta-turn formation were found. A statistically high agreement was found between these six sequences and three areas in alpha-gliadin with the occurrence of Pro-Ser-Gln-Gln sequence which has recently been considered responsible for toxicity in coeliac disease. By means of solid-phase synthesis seven peptides were obtained covering the above-mentioned regions. Their toxicity was tested using the fetal chick duodenum. The results support the suggestion that peptides containing the sequences Pro-Ser-Gln-Gln and Gln-Gln-Gln-Pro may be involved in the pathogenesis of coeliac disease.     

Isolation and enzymatic fragmentation of the coeliac-active gliadin peptide CT-1

Summary Investigations on the structure/toxicity relationships of gliadin peptides were continued with the coeliac-active gliadin peptide CT-1, which is derived from the N-terminal portion (residues 3–24 of the amino acid sequence) of-gliadins [this journal (1986) 182:115–117]. CT-1 was produced by chymotryptic digestion and reversed-phase (RP) HPLC from the peptide fraction G3 [this journal (1992) 194:1–6] and digested with the proteases endoproteinase Glu-C, pancreatin, papain and thermolysin. The fragment peptids were separated by preparative RP-HPLC and characterized by amino acid analysis. On the basis of the specifity of the enzymes for CT-1 and the toxic effect of enzymatic hydrolysates of gliadin described in the literature, the significance of partial sequences, in particular of the sequence -Pro-Ser-Gln-Gln-Gln-Pro- for the coeliac-toxicity effect, is discussed.

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Isolierung und enzymatische Fragmentierung des coeliakieaktiven Gliadinpeptids CT-1

Zusammenfassung Die Untersuchungen über die Zusammenhänge zwischen der Struktur von Gliadinpeptiden und ihrer Toxizität wurden mit dem coeliakieaktiven Gliadinpeptid CT-1 fortgesetzt, das aus dem N-terminalen Bereich (Positionen 3–24 der Aminosäuresequenz) von-Gliadinen stammt [diese Zeitschrift (1986) 182:115–117]. CT-1 wurde aus der Peptidfraktion G3 [diese Zeitschrift (1992) 194:1–6] durch chymotryptische Partialhydrolyse und Umkehrphasen-HPLC gewonnen und mit den Proteasen Endoproteinase Glu-C, Pankreatin, Papain und Thermolysin umgesetzt. Die entstandenen Fragmentpeptide wurden durch präparative Umkehrphasen-HPLC getrennt und durch Aminosäurenanalyse charakterisiert. Anhand der Spezifität der Enzyme gegenüber CT-1 und der aus der Literatur bekannten toxischen Wirkung von enzymatischen Gliadinhydrolysaten wird die Bedeutung einzelner Sequenzabschnitte, insbesondere der Sequenz-Pro-Ser-Gln-Gln-Gln-Pro-, für die coeliakiespezifische Wirkung diskutiert.

     

Amino-acid sequence of the coeliac active gliadin peptide B 3142

Summary Peptide B 3142, which has been isolated from a peptic tryptic digest of whole gliadin by several separation steps [1], was examined for coeliac activity in an immunological test and in an organ-culture test, comparing enlarged groups of coeliac patients and control persons. In both test systems the peptide shows a coeliac specific effect.The N-terminal sequence analysis (EDMAN degradation), the C-terminal sequence analysis (incubation with carboxypeptidase Y) and the sequence determination of peptides, obtained from B 3142 by digestion with papain and chymotrypsin, result in the following total amino-acid sequence: H-Val-Pro-Val-Pro-Gln-Leu-Gln-Pro-Gln-Asn-Pro-Ser-Gln-Gln residues correspond to a molecular mass of 6,129 g/mol.

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Aminosäuresequenz des coeliakieaktiven Gliadinpeptids B 3142

Zusammenfassung Das in vorangegangenen Arbeiten [1] aus einem peptisch-tryptischen Partialhydrolysat von Gliadin über einen mehrstufigen Trennprozeß gewonnene Peptid B 3142 wurde an einem erweiterten Patientenkreis im immunologischen Test und im Organkultur-Test auf Coeliakie-Aktivität geprüft. In beiden Tests zeigt das Peptid eine Coeliakie-spezifische Wirkung. Die N-terminale Sequenzanalyse (EDMAN-Abbau), die C-terminale Sequenzanalyse (Umsetzung mit Carboxypeptidase Y) sowie die Sequenz-analyse von Spaltpeptiden aus den mit Papain und Chymotrypsin erhaltenen Partialhydrolysaten ergeben folgende, aus 53 Aminosäureresten bestehende Gesamtsequenz: H-Val-Pro-Val-Pro-Gln-Leu-GlnPro-Gln-Asn-Pro-Ser-Gln-Gln-Gln-Pro-Gln-Glu Gln-Val-Pro-Leu-Val-Gln-Gln-Gln-Gln-Phe-Pro-Gly-Gln-Gln-Gln-Pro-Phe-Pro-Pro-Gln-Gln-Pro-Tyr-Pro-Gln-Pro-Gln-Pro-Phe-Pro-Ser-Gln-Gln-Pro-Tyr-OH. Daraus errechnet sich eine Molmasse von 6129 g/mol.

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Supported by grants from Stiftung Volkswagenwerk and from Deutsche Forschungsgemeinschaft

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We gratefully acknowledge the excellent assistance given by Mrs. Schiltzler     

Isolation and enzymatic fragmentation of the coeliac-active gliadin peptide CT-1.

Investigations on the structure/toxicity relationships of gliadin peptides were continued with the coeliac-active gliadin peptide CT-1, which is derived from the N-terminal portion (residues 3-24 of the amino acid sequence) of alpha-gliadins [this journal (1986) 182:115-117]. CT-1 was produced by chymotryptic digestion and reversed-phase (RP) HPLC from the peptide fraction G3 [this journal (1992) 194:1-6] and digested with the proteases endoproteinase Glu-C, pancreatin, papain and thermolysin. The fragment peptides were separated by preparative RP-HPLC and characterized by amino acid analysis. On the basis of the specificity of the enzymes for CT-1 and the toxic effect of enzymatic hydrolysates of gliadin described in the literature, the significance of partial sequences, in particular of the sequence -Pro-Ser-Gln-Gln-Gln-Pro- for the coeliac-toxicity effect, is discussed.     

The effect of microwave treatment on the immunoreactivity of gliadin and wheat flour

Commercial gliadins and wheat flour were exposed to microwaves at power distribution of 70, 200, and 500 W for different time periods to achieve a level of applied energy doses up to 150 kJ. Ethanolic extracts (40 vol.% ethanol/water) of microwave treated samples were analyzed by ELISA with the use of either monoclonal antibodies against -gliadin or polyclonal anti-gliadin antibodies and by electrophoresis followed by immunoblotting. A significant increase in reactivity, almost 210% over the untreated control sample, was observed for gliadins exposed to the energy dose of 40 kJ. Gliadins treated with higher energy doses showed a drop in an immune response independent of monoclonal or polyclonal antibodies used in ELISA. Gliadin fractions extracted from wheat flour treated with microwaves demonstrated similar immunoreactivity changes vs applied energy, although the maximum of reactivity appeared at 30 kJ. The increase in immune response of microwave irradiated gliadins was also confirmed by immunoblotting assay with the use of sera of patients susceptible to wheat flour allergy. Reversed phase HPLC elution profiles of treated gliadins showed that the content of all gliadin fractions in microwave treated samples decreased with the increase of the dose of applied energy.     

Relationship between the colour and the chemical structure of carotenoid pigments

Several carotenoids were isolated and their colours were ascertained objectively to establish relationships between the chemical structures of those pigments and their actual colours, considering the coordinates of the uniform space CIELAB. The results of this study revealed that the different carotenoids surveyed could be grouped in the a^∗b^∗ plane according to the number of conjugated double bonds. For yellowish carotenoids, it was observed that a^∗ values clearly decreased from those with 11 conjugated double bonds (c.d.b.) to those with 9 c.d.b., although this trend reversed in the case of carotenoids with 7 c.d.b.. In terms of hue (h_ab), it was seen that the decrease in conjugation of the molecules involved a slight rise in h_ab. On the other hand, the aperture of the end rings or the increase in conjugation involved clear increases in hue.     

精纺毛织物抗皱性能与织物结构参数的关系

采用相同的后整理工艺,研究了原料细度、捻系数、织物总紧度和纬经比对毛织物抗皱性能的影响。结果表明,纤维越细,织物抗皱性能越好;降低经纱捻系数或增加纬纱捻系数,均可提升织物的抗皱性能;组织结构不同,织物总紧度和纬经比对抗皱性能的影响程度也不尽相同。     

OPTIM形态尺寸记忆性与其结构之间的关系

OPTIM纤维细化过程中,由于分子中二硫键-S-S-的记忆性、拉伸时的内应力及塑性变形的变化,使OPTIM与原毛、羊绒相比,纤维弹性回复率、缩绒性减小;湿润胀性、松弛收缩率增大,纤维形态记忆性降低.文章分析了OPTIM大分子结构、超分子结构及形态结构变化与织物形态记忆性的关系,提出了提高OPTIM纤维及织物形态尺寸记忆性的措施.     

薄型精纺毛织物刚柔性与织物结构参数的关系

以14种精纺薄型毛织物为例,采用斜面悬臂法测定织物的经向和纬向抗弯长度,根据试验数据分析原料和织物组织对织物刚柔性的影响,并运用Origin7.0分析纱线的捻度、线密度,织物的厚度、经密和纬密与织物刚柔性的关系。分析得出:织物刚柔性与构成织物原料的性能、纱线的结构和织物结构有很大的关系。原料的初始模量越小,织物的柔软度越好;纱线的捻度越大,织物的柔软度越差,纱线的线密度越大,织物呈现刚性;平纹组织的刚性大于斜纹组织,织物越厚,织物越呈现刚性,在其他参数相同的情况下,织物经、纬密增加时,织物的抗弯长度增大,织物越呈现刚性。     

大豆肽分子量与缓解疲劳作用关系的研究

为了研究大豆肽分子量与缓解疲劳作用的关系,分别给小鼠灌胃不同分子量的大豆肽,然后测定缓解疲劳指标,包括体重、游泳时间、血清尿素氮含量、肝糖原含量和血乳酸含量。试验结果表明,大豆肽对小鼠体重变化影响不显著,但是游泳时间延长,血清尿素氮含量降低,肝糖原含量提高,血乳酸含量降低。其中相对分子质量为875和500的大豆肽对缓解疲劳指标影响显著。大豆肽分子量越小,缓解疲劳作用效果越明显。     

毛织物的服用性能与纱线和织物结构的关系

文章从手感、折皱恢复性、尺寸稳定性、起球、耐磨性、断裂强度等几方面论述了毛织物的服用性能与纱线和织物结构的关系,并指出毛织物设计中应注意的问题,为纺织技术人员提供有参考价值的理论指导.     

篷网基布孔眼结构形式与力学性能的关系

以涤纶纤维为原料,在织物密度、纱线线密度等参数相同的情况下,分别织制不同的花式透孔织物,得到孔眼结构形式不同的织物,然后进行拉伸强力实验和撕裂强力实验,确定最佳机械强力下的织物孔径分布参数,从而优选出最佳孔眼结构的篷网基布的织物。     

Relationship between strength of organic sorbate interactions in NOM and hydration effect on sorption

According to a recent conceptual model for hydration-assisted sorption of organic compounds in natural organic matter (NOM), certain polar moieties of dry NOM are unavailable for compound sorption due to strong intra- and intermolecular NOM interactions. Water molecules solvate these moieties creating new sorption sites at solvated contacts. It is expected that the greater a compound's ability to undergo specific interactions with NOM, the greater will be the hydration-assisted sorption effect, because penetration of compounds into solvated contacts must involve competition with water at the solvated contact. To test this model, we compare the hydration effect on sorption kinetics and equilibrium for 4 compounds with differing abilities to undergo specific interactions with NOM. Sorption measured on Pahokee peat in aqueous systems was fast compared with n-hexadecane (dry) systems. No concentration effect on attainment of sorption equilibrium was observed. m-Nitrophenol exhibited the greatest hydration-assisted sorption effect, benzyl alcohol showed an intermediate effect and acetophenone and nitrobenzene showed no hydration-assisted sorption, on an activity scale. The extent of hydration-assisted sorption effect correlates with compound ability to undergo specific interactions. These results support the conceptual model and demonstrate the importance of polar NOM noncovalent links in organizing the NOM phase and in controlling the hydration effect on sorption of organic compounds.     

Association between electrophoretic patterns of gliadin proteins and quality characteristics of wheat cultivars

Electrophoretic patterns for cereal-grain prolamins were coded in numerical form to permit computer-based comparison, either for facilitating the identification of cultivars or for the study of genotypic relationships. In a group of 80 cultivars, including wheats grown in countries other than Australia, gliadin patterns reflected both pedigree and taxonomic relationships, particularly in the separate grouping of a rye, and of durum and club wheats. Certain gliadin bands were also found to be significantly associated with the quality characteristics of hardness and dough strength.     

三维机织复合材料的结构与材料力学性能的关系

介绍了开发三维机织增强复合材料的目的 ,主要阐述了复合材料的预型件结构及其与力学性能 (纵向拉伸弹性模量 )之间的关系     

Relationship between fat depots in carcasses of beef bulls and effect on meat colour and tenderness

The growth and the effects of four species of staphylococci and six lactic acid bacteria (LAB) of the genus Carnobacterium, Lactobacillus and Pediococcus on unsaturated free fatty acids were studied. The strains were grown in complex medium supplemented either with oleic, linoleic or linolenic acids. Growth was followed and oxidation of the substrates measured by TBARS. The strains of Staphylococcus xylosus 873, 16, Staphylococcus warneri 863 and Staphylococcus saprophyticus grew well on all the substrates. Whereas, the growth of the two strains of Staphylococcus carnosus and Staphylococcus xylosus 831 was inhibited in the media with linolenic acid. The addition of manganese to this media allowed good growth of these strains. All the LAB did not grow well in the media with linoleic acid, but their growth was favoured by addition of manganese to the media. Under our conditions, only linoleic and linolenic acids were oxidised. All the strains had no prooxidant activity. All the staphylococci limited oxidation of linoleic acid and had a small effect on linolenic acid. LAB did not limit oxidation of linoleic acid. With manganese in the media: the oxidation of the sterile controls was delayed for 2 days and then increased; strains of S. carnosus and S. xylosus inhibited oxidation of linolenic acid; and Lactobacillus plantarum and Pediococcus pentosaceus limited oxidation of linoleic acid. The two Carnobacterium, whatever the conditions, had no antioxidant properties.     

脂质中的蛋白质与多肽及其对脂质品质的影响

脂质中蛋白质和多肽的存在在一定程度上影响了脂质的品质.本文介绍了植物油和磷脂产品中蛋白质与多肽的分离和分析方法,并对其在脂质氧化稳定性、食品安全性(主要是过敏性)方面的影响进行了详细的论述,以期为脂质产品品质的提高提供参考.     

面包辅料与其体积关系的研究

面包的体积是评价其品质的重要指标之一,研究辅料对面包体积的影响无疑具有重要意义。面包常用辅料主要有白砂糖、油脂、乳粉、鸡蛋4种,通过改变辅料的用量,研究其对面包体积的影响规律。试验结果表明,添加适量辅料,都能增加面包体积,辅料适宜添加范围为:白砂糖4%～8%,油脂5%～8%,乳粉4%～6%,鸡蛋6%～10%。     

Interaction between the peptide glutathione and linoleic acid hydroperoxide

Incubation experiments in order to study the influence of some parameters in the fluorescence products formation have been carried out. It has been observed a greater efficiency with the relation linoleic acid hydroperoxide:glutathione, 2:1, and a temperature of 37 °C. The complex formed working with labelled linoleic acid has been separated in two main fractions. The first one (without radioactivity) is fluorescent with excitation and emission maxima at 350 nm and 440 nm, respectively. It has been confirmed that this fraction consists of a complex of glutathione and short chain aldehydes. The fluorescence of the complex did not decrease by treatment with NaBH₄ or with pH. The NH₂ and SH groups take part in the lipid-peptide complex formation. The second, highly radioactive fraction includes free hydroperoxides and short chain hydroxy fatty acids.     

The effect of diet with an increased amount of tyrosine on reparative processes in the duodenum

It has been shown that the development of destructive lesions of the duodenal wall induced by stress action on the body of the experimental animal is attended by a decrease of the content of creatine phosphate and noradrenaline in homogenate of the duodenal tissue. The use of tyrosine, a precursor of catecholamine biosynthesis, both as a pharmacologic agent and as a component of rich in this amino-acid product-dried milk, resulted in normalization of the biochemical parameters studied and in significant diminution of destructive lesions of the duodenal wall.