Allergenicity of proteolytic hydrolysates of the soybean 11S globulin

ABSTRACT:  A substantial portion of the human population has immune hypersensitivities to various food materials. Soybean is one of the most common foods involved in such hypersensitivity reactions, especially in younger children. In this study, we investigated the effect of peptic and chymotryptic hydrolysis on the allergenicity of the 11S soybean globulin, which is the primary soybean allergen. The 11S globulin is composed of both acidic and basic polypeptides, and we found that the acidic polypeptide was effectively hydrolyzed, while basic polypeptide was more resistant to hydrolysis. The 11S globulin hydrolysate was size-fractionated by gel filtration, and 9 of the fractions obtained were tested for allergenicity against sera from 6 soybean-allergenic patients. The overall allergenicity of soybean 11S globulin was reduced by peptic and chymotryptic hydrolysis, although a gel filtration fraction with a major peptide of 20 kDa was highly immunoreactive. Hydrolyzed fragments of less than about 20 kDa were not immunoreactive.     

大豆球蛋白和清蛋白水法提取工艺研究

采用水法从低温豆粕和高温豆粕中提取球蛋白和清蛋白,通过单因素实验和正交实验对提取工艺进行优化,并研究了pH对蛋白质提取率的影响。结果表明:低温豆粕和高温豆粕清蛋白水法提取的最佳工艺条件为料液比1∶12、提取时间2.0 h、提取温度45℃,此时清蛋白提取率分别为66.41%、24.89%;低温豆粕球蛋白水法提取的最佳工艺条件为料液比1∶8、提取时间3.0 h、提取温度50℃、Na Cl溶液质量分数4%,此时球蛋白提取率为21.86%;高温豆粕球蛋白水法提取的最佳工艺条件为料液比1∶14、提取时间2.0 h、提取温度50℃、Na Cl溶液质量分数4%,此时球蛋白提取率为16.98%。在最佳工艺条件下,pH在7~11时低温豆粕清蛋白提取率分别提高了0.65、4.99、10.59、8.91、10.99个百分点,pH在8~11时高温豆粕清蛋白提取率分别提高了2.46、10.29、26.24、37.86个百分点,pH在4~6时低温豆粕和高温豆粕球蛋白提取率分别提高了7.74、13.30、2.94个百分点和4.45、5.13、3.27个百分点。     

谷氨酰胺转胺酶对大豆7S蛋白质及肌球蛋白质胶凝性质的影响

大豆7S蛋白与肌球蛋白质经谷氨酰胺转胺酶（TGase）作用后,产物的十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)结果表明,两者均可在分子间生成共价键,形成相对分子质量较大的聚合物.10g/dL肌球蛋白质溶液加入10U/g的TGase,于35℃、pH7.0的条件下反应90min,体系的凝胶强度较对照组有了很大提高.10g/dL大豆分离蛋白质溶液与0.02U/mg的TGase在37℃下保温150min后,体系粘度增加了150mPa*s;而5g/dL的肌球蛋白质加酶并于10℃下保温180min后,其粘度值提高了600mPa*s.     

大豆球蛋白的纤维聚集体行为及其稳定性研究

为了明确蛋白质的纤维聚集行为,本研究以大豆球蛋白(soy globulin,11S)为原料,从亚基层面对酸性条件下热诱导的11S纤维聚集过程进行跟踪,监测蛋白及其亚基的水解过程、结构变化及其稳定性。结果表明,11S的纤维化是一个多步骤的过程,包括多肽链的水解、自组装成淀粉样纤维聚集结构及逐渐生长成宏观可见的具有扭曲螺旋结构的纤维聚集体。与11S纤维化过程的单指数增长相比,酸性亚基的纤维化过程存在迟滞期。酸性亚基在纤维化聚集的初期主要贡献于纤维聚集的成核过程,碱性亚基的加入改变其纤维聚集进程。蛋白质的纤维化过程会增加11S在等电点处的溶解度,降低中性和酸性pH下的溶解度。此外,碱性环境(pH值10.0)会导致11S纤维聚集体全部溶解、宏观纤维长度变小、结构发生改变。以上研究结果旨在为合理利用蛋白纤维化聚集体作为新的功能性食品配料提供理论依据。     

Binding of aroma compounds with legumin. III. Thermodynamics of competitive binding of aroma compounds with 11S globulin depending on the structure of aroma compounds

This paper considers the prominent features in competitive binding of aroma esters from their mixtures to 11S globulin of broad beans (legumin) in aqueous medium at pH 7.2 and ionic strength of 0.05 mol dm⁻³. Series of alkyl acetates (C₄–C₈) and methyl esters of carbonic acids (C₅–C₉), differing in the length of hydrocarbon chain, have been under our studying. To accomplish the ends of the study, a combination of ultrafiltration and gas–liquid chromatography (GC) has been used. An increase in the length of hydrocarbon chain of the aroma esters brought about greater binding affinity for the protein, the occurrence of some structural restrictions in the interior of the protein molecule, preventing binding, and the change in the binding mechanism of the aroma compounds at the specific critical length of hydrocarbon chain. Differential scanning microcalorimetry data suggested that the revealed changes in the binding mechanism of the studied aroma compounds were attributable to the conformational modification of the protein globule as a result of binding with the aroma compounds. A distinguishing feature in binding of methyl esters of carbonic acids with legumin was their greater binding affinity for the protein as compared with alkyl acetates. The mutual effect of aroma compounds on binding from their equimolar mixtures to the protein made itself evident, firstly, as a drastic increase in the binding extent of aroma esters, having rather long hydrocarbon chain and, secondly, as a dramatic change in the binding mechanism of the aroma esters with relatively short hydrocarbon chain.     

阿奇霉素联合红霉素治疗儿童支原体肺炎及对免疫功能的影响

目的探讨阿奇霉素联合红霉素治疗支原体肺炎患儿的疗效及对免疫功能的影响。方法2007年3月至2009年4月我科收住院的临床诊断为支原体肺炎的患儿,分为治疗组(阿奇霉素联合红霉素治疗)和对照组(红霉素治疗),比较2组治疗疗效,并分别采用免疫比浊法及ELISA法测定血清免疫球蛋白及血清支原体抗体IgM(MP-IgM)。结果治疗组有效率(94.4%)较对照组(77.5%)高(χ2=17.135,P<0.01),不良反应较对照组少(χ2=5.457,P<0.05),在退热时间和啰音消失时间等方面指标均较对照组短(P<0.05),咳嗽缓解时间方面2组之间差异无统计学意义(P>0.05)。治疗后,2组血清IgA、IgG、IgM水平均较治疗前明显降低(P<0.05),治疗组治疗后血清IgA、IgG、IgM水平较对照组治疗后更低,差异有统计学意义(P<0.05)。结论阿奇霉素联合红霉素治疗支原体肺炎,具有良好的临床效果和安全性,值得临床推广应用。     

Lack of Globulin Synthesis during Seed Development Alters Accumulation of Seed Storage Proteins in Rice

The major seed storage proteins (SSPs) in rice seeds have been classified into three types, glutelins, prolamins, and globulin, and the proportion of each SSP varies. It has been shown in rice mutants that when either glutelins or prolamins are defective, the expression of another type of SSP is promoted to counterbalance the deficit. However, we observed reduced abundances of glutelins and prolamins in dry seeds of a globulin-deficient rice mutant (Glb-RNAi), which was generated with RNA interference (RNAi)-induced suppression of globulin expression. The expression of the prolamin and glutelin subfamily genes was reduced in the immature seeds of Glb-RNAi lines compared with those in wild type. A proteomic analysis of Glb-RNAi seeds showed that the reductions in glutelin and prolamin were conserved at the protein level. The decreased pattern in glutelin was also significant in the presence of a reductant, suggesting that the polymerization of the glutelin proteins via intramolecular disulfide bonds could be interrupted in Glb-RNAi seeds. We also observed aberrant and loosely packed structures in the storage organelles of Glb-RNAi seeds, which may be attributable to the reductions in SSPs. In this study, we evaluated the role of rice globulin in seed development, showing that a deficiency in globulin could comprehensively reduce the expression of other SSPs.     

小剂量丙种球蛋白联合糖皮质激素治疗儿童特发性血小板减少性紫癜的Meta分析

目的 系统评价小剂量丙种球蛋白（IVGG）联合糖皮质激素治疗儿童特发性血小板减少性紫癜（ITP）的临床疗效.方法 检索2000-2013年中国期刊网、万方数据库及中国生物医学文献数据库,获得国内已发表的小剂量IVGG联合糖皮质激素治疗儿童ITP的相关文献.比较小剂量、大剂量IVGG联合糖皮质激素治疗儿童ITP的总有效率,并用CochranelRev Man5.0统计软件进行Meta分析.结果 共检索到符合条件的文献5篇,小剂量组总有效率与大剂量组比较差异无统计学意义（Z＝0.72,P＞0.05）.结论 小剂量IVGG联合糖皮质激素可以取得与标准剂量IVGG联合糖皮质激素治疗基本相同的疗效,对于儿童ITP建议采用小剂量IVGG联合糖皮质激素治疗.     

汉麻球蛋白酶解产物中巯基肽的含量及分布研究

采用DTT还原结合Sephadex LH-20葡聚糖凝胶层析的方法分离测定了汉麻球蛋白3种酶解产物中巯基肽的含量,测定结果显示：碱性蛋白酶>胃蛋白酶>木瓜蛋白酶。采用LC-MS-MS检测并鉴定出3种蛋白酶酶解物中巯基肽的分布和序列,结果显示：碱性蛋白酶酶解物中巯基肽数量为41个,木瓜蛋白酶和胃蛋白酶酶解物中都是31个,来源均是Edestin2、Edestin3、清蛋白和非特征蛋白。3种酶酶解获得的麻仁球蛋白(Edestin)巯基肽大部分为亲水性的,分子质量主要分布于1 000～2 000 u,其中10个是3种酶解产物共有的,碱性蛋白酶和胃蛋白酶酶解物中有4个相同的来源于Edestin3的麻仁球蛋白巯基肽。胃蛋白酶酶解得到1个独有的源于Edestin2的麻仁球蛋白巯基肽。碱性蛋白酶酶解得到了4个独有的源于Edestin3的麻仁球蛋白巯基肽。3种蛋白酶由于作用位点和效力不同得到的麻仁球蛋白巯基肽数量和分布均有不同,但是碱性蛋白酶酶解汉麻球蛋白可以获得更多的麻仁球蛋白巯基肽,推测碱性蛋白酶可以更好地打开汉麻球蛋白中的二级及以上结构,使二硫键更多地暴露出来。     

Textural properties and morphology of soy 7S globulin-corn starch (amylose,amylopectin)

The texture properties (hardness, adhesiveness, cohesion, elasticity) of composite gels with different ratios (0:100, 6:94, 8:92, 10:90, 12:88, and 14:86, respectively) of soy 7S globulin to corn starch (amylose, amylopectin) were studied. Furthermore, the morphology and crystal structure of the mixed gels were investigated. The results showed: the addition of soy 7S globulin could weaken the hardness of corn starch (amylose, amylopectin) and increased the adhesiveness of corn amylose significantly (p < 0.05). Generally, when the additive amount of soy 7S globulin was 10%, the composite gels of soy 7S globulin and corn starch (amylose, amylopectin) appeared to have the best consistency, cohesion, and elasticity.