去胚轴对花生子叶肽链内切酶和贮藏蛋白质降解的影响

从离体子叶与连体子叶在水中培养一段时间后的比较,看到它们之间在肽链内切酶活性和盐溶蛋白及花生球蛋白降解上的差异并不大,这表明去除胚轴对子叶肽链内切酶活性和贮藏蛋白降解的影响很轻微。亚胺环己酮(蛋白质合成抑制剂)不能完全抑制离体子叶肽链内切酶活性的提高,子叶的大部分大分子贮藏蛋白同样被降解。这表明,在花生种子萌发过程中降解大部分贮藏蛋白的子叶肽链内切酶并非全部是在种子萌发时新合成的,子叶贮藏蛋白降解和肽链内切酶活性基本不受胚轴调控,子叶与胚轴之间在调控关系上可能是一种新的调节类型。     

去胚轴对花生子叶肽链内切酶和贮藏蛋白质降解的影响

从离体子叶与连体子叶在水中培养一段时间后的比较,看到它们之间在肽链内切酶活性和盐溶蛋白及花生球蛋白降解上的差异并不大,这表明去除胚轴对子叶肽链内切酶活性和贮藏蛋白降解的影响很轻微。亚胺环己酮（蛋白质合成抑制剂）不能完全抑制离体子叶肽链内切酶活性的提高,子叶的大部分大分子贮藏蛋白同样被降解。这表明,在花生种子萌发过程中降解大部分贮藏蛋白的子叶肽链内切酶并非人全部是在种子萌发是新合成的。子叶贮藏蛋白降     

花生种子的发育与贮藏蛋白质的合成和积累

花生果针入土后16天(16 DAP),种子干重和鲜重开始迅速增加。整个发育阶段可分为5个时期:组织分化期(0～20 DAP)、成熟前期(21～28 DAP)、成熟中期(29～40DAP)、成熟中后期(41～62 DAP)和成熟后期(63～88DAP)。种子发芽率在成熟前期和中期迅速提高并到达最大值,而苗成活率在成熟中后期达到最大值,苗鲜重则以88 DAP种子的为最大。种子发育过程中,贮藏蛋白质的合成与积累模式与种子干重变化相似。SDS-PAGE分析表明,种子发育初期(16 DAP)子叶中已积累花生球蛋白和伴花生球蛋白I。双向凝胶电泳显示花生球蛋白各个亚基在20DAP时均已存在,伴花生球蛋白I的主要亚基在整个发育过程中其等电点有所变化,含量也逐渐增加。其他蛋白质在种子发芽力形成阶段(20～40 DAP)的变化较为显著。     

发育和早萌中花生胚胚轴与子叶内BAPAase活性的差异

花生胚发育过程中,子叶和胚轴中都出现BAPAase活性。花生种子萌发时,子叶和胚轴中的BAPAase活性迅速上升,子叶中无新的BAPAase合成,胚轴中能重新合成BAPAase。ABA抑制了子叶和胚轴中BAPAase的活性,抑制胚轴中BAPAase活性所需的外源ABA浓度更高,Act-D和CHM不能逆转ABA对BAPAase活性的抑制作用。     

萌发中花生胚轴的耐干性与热稳定蛋白

成熟花生种子吸胀１８ ｈ 发芽率达１００ ％ 。在这１８ ｈ 的范围内,胚轴即使经干燥处理,萌发生长率仍保持１００ ％ ,而热稳定蛋白含量变化很小。吸胀２４ ｈ 后,经干燥的花生胚完全丧失萌发生长能力。ＳＤＳＰＡＧＥ和双向电泳表明,花生胚轴的热稳定蛋白主要是贮藏蛋白,该蛋白中的花生球蛋白大亚基,伴花生球蛋白Ｉ和２Ｓ 蛋白的降解与胚轴的耐干性丧失有关。     

萌发中花生胚轴的耐干性与热稳定蛋的

成熟花生种子吸胀１８ｈ发芽率达１００％,在这１８ｈ的范围内,胚轴即使经干燥处理,萌发生长率仍保持１００％,而热稳定蛋白含量变化很小。吸胀２４ｈ后,经干燥的花生胚完全丧失蓝发生长能力。ＳＤＳ－ＰＡＧＥ和和双向电泳表明,花生胚轴的热稳定蛋白主要是贮藏蛋白,该蛋白中的花生球蛋白大亚基,伴花生球蛋白Ｉ和２５蛋白的降解与胚轴的耐干性丧失有关。     

脱水敏感的黄皮种子在发育中的可溶性蛋白变化

黄皮种子的子叶与胚轴,在发育前期蛋白质合成速率均高于后期。在发育过程中子叶的可溶性蛋白含量无明显变化,但在后期能新合成少数低分子量的热不稳定蛋白,可能是引起种子萌发的水解酶类。胚轴中可溶性蛋白单位干重含量高于子叶,而其成分不随发育而变化。ABA可促进发育后期黄皮种子胚轴中20kD蛋白的合成,但不能改变种子的脱水敏感性。     

不同芸豆品种种子发育过程中贮藏蛋白积累研究

以半蔓生型奶花芸豆(Y09)和直立型奶花芸豆(Y06)为材料,通过SDS-PAGE分析研究了开花后种子形成过程中贮藏蛋白(SP)的积累规律.结果表明:2个芸豆品种开花后种子形成过程中,子叶、胚蛋白积累变化趋势基本一致,但其变化幅度存在显著差异,其中,在开花后20d内,半蔓生型芸豆Y09的籽粒蛋白积累量大于直立型芸豆Y06,但在开花后25~40d,Y06籽粒蛋白积累量显著高于Y09;两芸豆品种的子叶和胚均含有丰富的贮藏蛋白(SP)(14.4~97.4kD),其中子叶的41.0、43.9、39.4kD3种蛋白含量较高,约占子叶总蛋白含量(光密度)50%以上,而胚蛋白亚基分布相对均匀;两品种的子叶、胚中蛋白亚基差异较小,只有个别亚基存在差异.     

脱落酸和抑制剂对萌发花生子叶肽链内切酶和花生球蛋白降解的影响

脱落酸（Ａｂｓｃｉｓｉｃａｃｉｄ,ＡＢＡ）抑制花生种子萌发的作用与核酸和蛋白质合成抑制剂的作用不同．ＡＢＡ（１００μｍｏｌ／Ｌ）在萌发零时施用,明显抑制肽链内切酶活性和同工酶表现以及花生球蛋白降解,萌发４８ｈ施用ＡＢＡ（１００μｍｏｌ／Ｌ）只降低肽链内切酶活性．ＡＢＡ的抑制作用不依赖于核酸和蛋白质合成．核酸合成抑制剂（３＇－脱氧腺苷,放线菌素Ｄ,５－氟尿嘧啶）和蛋白质合成抑制剂（亚胺环己酮）只能部分降低肽链内切酶活性,对肽链内切酶同工酶表现和花生球蛋白降解无明显影响．实验结果表明花生子叶肽链内酶不是在种子萌发过程中重新（ｄｅｎｏｖｏ）合成,文中讨论了肽链内切酶活性调节和花生贮藏蛋白降解的起始模式．     

发育和早萌中花生胚胚轴一子叶内BAPAase活性的差异

花生胚发育过程中,子叶和胚轴中都出现ＢＡＰＡａｓｅ活性,花生种子明发时,子叶和胚轴中的ＢＡＰＡａｓｅ活性迅速上升,子叶中无新的ＢＡＰＡａｓｅ合成,胚轴中能重新合成ＢＡＰＡａｓｅ。ＡＢＡ抑制子叶和胚轴中ＢＡＰＡａｓｅ的活性,抑制胚轴中ＢＡＰＡａｓｅ活性所需的外源ＡＢＡ浓度更高,Ａｃｔ＝Ｄ和ＣＨＭ不能逆ＡＢＡ对ＢＡＰＡａｓｅ活性的抑制作用。     

The Relation of Storage Protein to Vigor and Its Mobilization Pattern in Germinating Peanut Seeds

The peanut (Arachis hypogaea L.) seeds harvested at the last stage of maturation were divided into five grades by size. The content of total protein, salt-soluble protein, arachin, conarachin I and 2s globulin in these seeds were measured. No obvious differences in germination percentage and the length of radicle and hypocotyl within 3d germination in dark were observed among the five grades of seeds. But there were significant differences in the seedling growth after two weeks of germination in light. There was a very close correlation between the storage protein in cotyledons and the seedling growth. When seeds germinated in light, the efficiency of mobilization of the salt-soluble protein in the cotyledons was higher than that in the cotyledons of the seeds germinating in dark. All of the salt-soluble protein in cotyledons was used up after 14d seedling growth in light. SDS-PAGE of salt-soluble protein showed that 23.5, 38.5 and 41 kD subunits of arachin were first mobilized during germination. The 18 kD subunits of arachin were not mobilized until the above-mentioned subunits were used up. The 60.5 kD subunit of conarachin I and 2s globulin were degradated within 2 to 3 days during germination.     

One and Two- dimensional Polyacrylamide Gel Electrophoretic Analysis of Seed Polypeptide Composition of Peanut Cultivars

Seed polypeptides from 46 cultivars of peanut (Arachis hypogaea L. ) were compared by SDS-PAGE and two-dimensional pelyacrylamide gel electrophoresis. Arachin, the major seed storage protein of peanut, showed polymorphism. There were four types of arachin pelypeptide pattems. Type Ⅰ consisted of only four major subunits:41 kD,38.5 kD and two of the 18 kD subunits. Type Ⅱ had six major subunits:41 kD,38.5 kD,37.5 kD and three of the 18 kD subunits. Type Ⅲ consisted of 41 kD, 38.5 kD,36.5 kD and three of the 18 kD subunits. And Type Ⅳ consisted of seven major subunits:41 kD,38.5 kD,37.5 kD,36.5 kD and three of the 18 kD subunits. The compositions of conarachin in different cultivars were similar. Amino acid composition analysis of seed protein in 8 peanut cuhivars showed that Type Ⅰ was rich in methionine and cystine.     

Association of thymidine and uridine kinase activities with changes in nucleic acid levels during peanut fruit ontogeny

Various stages of pegs, cotyledons and embryonic axes from maturing peanut fruits were examined for their ability to phosphorylate thymidine and uridine. Highest specific activities during peg elongation were found just prior to increases in endosperm nuclei and embryo cell numbers. In the developing cotyledons and axes, the net kinase activities of crude extracts reached a maximum 1–2 weeks before maximal RNA and DNA contents were attained. An exception was the apparent lack of any relationship between uridine kinase activities and RNA levels in developing embryonic axes. The present results support the observation that peanut axes are devoid of thymidine and uridine kinases during the first 24 hr of germination, as fully developed fruits had very low specific activities for both of these phosphate transferases.     

Characterization of Blue-Green Fluorescence in the Mesophyll of Sugar Beet (Beta vulgaris L.) Leaves Affected by Iron Deficiency

Protease C1, an enzyme from soybean (Glycine max [L.] Merrill cv Amsoy 71) seedling cotyledons, was previously determined to be the enzyme responsible for the initial degradation of the alpha' and alpha subunits, but not the beta subunit, of beta-conglycinin storage protein. The sizes of the proteolytic products generated by the action of protease C1 suggest that the cleavage sites on the alpha' and alpha subunits of beta-conglycinin may be located in their N-terminal domain, which is not found in the beta subunit of beta-conglycinin. To check this hypothesis, storage proteins from other plant species that are homologous to either the alpha'/alpha or the beta subunit of beta-conglycinin were tested as substrates. As expected, the convicilin from pea (Pisum sativum), a protein homologous to the alpha' and alpha subunits of beta-conglycinin, was digested by protease C1. The vicilins from pea as well as vicilins from adzuki bean (Vigna angularis), garden bean (Phaseolus vulgaris), black-eyed pea (Vigna unguiculata), and mung bean (Vigna radiata), storage proteins that are homologous to the beta subunit of soybean beta-conglycinin, were not degraded by protease C1. Degradation of soybean beta-conglycinin involves a sequential attack of the alpha subunit at multiple sites, culminating in the formation of a stable intermediate of 53.5 kD and a final product of 48.0 kD. The cleavage sites resulting in this formation of the intermediates and final product were determined by N-terminal analysis. These were compared to the known amino acid sequences of the three beta-conglycinin subunits. Results showed these two polypeptides to be generated by proteolysis of the alpha subunit at regions bearing long strings of acidic amino acid residues.     

蚕豆蛋白质亚基分析与特异种质鉴定

采用SDS-PAGE方法,对112份不同基因型蚕豆的清蛋白和球蛋白亚基的差异性进行分析。结果显示:(1)蚕豆清蛋白和球蛋白亚基的有效等位变异分别为1.750 0±0.452 3、1.545 5±0.522 2,多态性比率分别为75.00%、54.55%,清蛋白的亚基遗传多样性指数较球蛋白亚基高。(2)蚕豆清蛋白和球蛋白分别含有在不同基因型蚕豆中构成不同的12和10个亚基,其中清蛋白含有9个基本亚基,116kD、96kD、45kD为清蛋白的3个特异亚基;球蛋白含有8个基本亚基,58kD、35kD为球蛋白的2个特异亚基;研究共鉴定筛选出42个含有清蛋白特异亚基和21个含有球蛋白亚基的种质资源。(3)清蛋白的97kD、63kD基本亚基和球蛋白的97kD、56kD、47kD基本亚基存在一定的缺失现象,共鉴定出19个清蛋白亚基和21个球蛋白亚基缺失的优异种质。研究表明,蚕豆清蛋白和球蛋白亚基构成在不同种质之间具有差异性,除基本亚基外,部分种质还含有特异亚基或缺失亚基。     

小麦幼芽水分胁迫诱导蛋白的特征

水分胁迫（－1．2MPaPEG-6000）处理萌动的小麦种子,24h后诱导小麦幼芽产生41．5kD蛋白,其含量随着胁迫时间延长明显增加,48h时含量最高,到72h后不再变化。复水后,该蛋白消失;再胁迫48h时则又出现,其含量与处理24h时相当。41．5kD诱导蛋白主要位于细胞器膜上,细胞质中几乎不存在。41．5kD蛋白主要溶于10％NaCl提取液中,其等电点为pl5．65。该蛋白的氨基酸组成中,脯氨酸含量最高,其次为丙氨酸、天冬氨酸、谷氨酸、甘氨酸,没有发现半胱氨酸和组氨酸。     

菠菜叶片蔗糖磷酸合成酶的纯化

经硫酸铵分部沉淀,DEAE-纤维素(DE 52),Sepharose 6B和 AH—4B连续三次柱层析,得到纯化88倍电泳均一的菠菜叶片蔗糖磷酸合成酶。电泳分析该酶分子量为490 kD,是由八个分子量为60 kD的相同亚基组成的寡聚体,等电点为PI=4.l,其最适pH值为6.9。     

花生种子贮藏蛋白的氨基酸组成分析及发育过程中17.5 kDa多肽的合成规律

分析了两种不同蛋白质组成类型花生的子叶总蛋白３个主要组分及高甲硫氨酸类型花生的６０．５、４１、３８．５、１８和１７．５ｋＤａ多肽的氨基酸组成,结果表明它们均含有１７种氨基酸,其中天冬氨酸、谷氨酸和精氨酸含量最高,而甲硫氨酸含量和半胱氨酸水平都极低。高甲硫氨酸类型品种的各组分的甲硫氨酸含量均显著高于低甲硫氨酸类型品种的对应组分的甲硫氨酸含量,在这两种类型花生中伴花生球蛋白Ⅱ都是甲硫氨酸含量最高的组分