烙铁头蛇毒素纤维蛋白原溶酶研究:Ⅱ.对纤维蛋白原及凝血酶的作用

烙铁头（T.mucrosquamatus）蛇毒纤维蛋白原溶酶TMVFg能水解三肽底物Bz-Phe-Val-Arg-PNA，但对凝血酶的良好底物Cbz-Gly-Pro-Arg-PNA却活性甚低。TMVFg显著延长血浆凝血酶时间、血浆复钙时间及纤维蛋白原溶液凝血酶时间。同时，TMVFg体外也能延长全血凝固时间，表明具有抗凝作用。纤维蛋白原-纤维蛋白转换实验表明：TMVFg水解纤维蛋白原产生的纤维蛋白原断片（FDP）除具有抗凝血酶，抑制纤维蛋白聚合活性外，还能促进纤维蛋白的聚合。进一步用FPLC分离TMVFg水解人纤维蛋白原混合液，得两个FDP断片功能峰，FDP组分Ⅰ和FDP组分Ⅱ。其中FDP组分Ⅰ能抑制纤维蛋白凝块形成；FDP组分Ⅱ能促进纤维蛋白凝块形成，抑制TMVA（烙铁头蛇毒血小板活化素，它可不通过ADP、花生四烯酸途径而诱导血小板聚集），但对ADP诱导的家兔血小板聚集无影响。TMVFg对凝血酶水解三肽底物Cbz-Gly-Pro-Arg-PNA及凝固纤维蛋白原的活性也有一定抑制作用。实验证明，TMVFg抗凝的主要作用机理是其水解纤维蛋白原产生的断片对纤维蛋白原凝固的抑制作用、FDP断片抗凝血酶作用及TMVFg本身对凝血酶活性的抑制所引起的，但在二者之间，前者是主要的。从研究结果发现：TMVFg水解纤维蛋白原所产生的断片有一类能加速凝血酶凝固纤维蛋白原的过程，这就发现了FDP断片的新功能。它证明了FDP断片作为血液凝固、纤溶正反馈调节因子的功能。这一类FDP断片还能抑制TMVA诱导的血小板聚集，因此，烙铁头蛇毒纤维蛋白原溶酶TMVFg将成为研究血液凝固调节系统及血小板聚集第三条途径的强有力试剂。     

蛇毒中凝血酶样酶的研究

蛇毒中凝血酶样酶的研究韦世秀广西医科大学蛇毒研究所南宁５３００２１许多蝮亚科蛇毒中都含有一种氨基酸酯酶［１］,它催化纤维蛋白原分子特定部位Ａｒｇ－Ｇｌｙ肽键的裂解,释出血纤肽而转换为纤维蛋白。其作用与血浆凝血酶十分相似,因而称之为凝血酶样酶（Ｔｈｒｏ...     

蛇毒纤维蛋白原水解酶

蛇毒纤维蛋白原水解酶毛建平孙志贤（军事医学科学院放射医学研究所北京１００８５０）关键词蛇毒纤维蛋白质凝血酶样酶纤溶酶许多蛇毒中含有降解纤维蛋白原或纤维蛋白的酶类,它们作用于高等动物血液循环系统,防止中毒动物血液凝固以利于其它毒素迅速扩散和生效。人类于...     

蝮蛇(Agkistrodon halys Pallas)蛇毒类凝血酶的研究——Ⅰ.分离提纯及理化、酶学性质的鉴定

(1)浙江产蝮蛇蛇毒中含有三种具有精氨酸酯酶活力的组分。它们分别是激肽释放酶、类凝血酶及类溶血纤维酶。其中类凝血酶的精氨酸酯酶活力最高,约占总酯酶活力的60%。(2)提纯后的类凝血酶在聚丙烯酰胺凝胶电泳上呈一条区带。经凝胶过滤及SDS 聚丙烯酰胺凝胶电泳测定,其分子量约43,000。氨基酸组成分析表明含有较多的酸性氨基酸及脯氨酸,此外还含有约6%的中性糖,9%的己糖胺及3.3%的唾液酸。(3)类凝血酶能直接使血纤维蛋白原凝聚,水解BAEE 的活力约是胰蛋白酶的2.7倍,K_(?)为3.4×10~(-4)M,高于其它已知的蝮亚科蛇毒类凝血酶活力。它不作用于BANA、BAPA 及其它蛋白底物。蛇毒类凝血酶与人凝血酶一样,对专一萤光底物Boc-Val-Pro-Arg-MCA 都有明显活力,但其凝结血纤维蛋白原的活力却远低于人凝血酶。(4)类凝血酶能被DFP 及PMSF 所抑制,但抑制速度缓慢,不能被胰蛋白酶的专一抑制剂TLCK 所抑制,因而是专一性很强的丝氨酸蛋白酶。     

蝮蛇(Agkistrodon halys Pallas)蛇毒类凝血酶的研究——Ⅰ.分离提纯及理化、酶学性质的鉴定

(1) 浙江产蝮蛇蛇毒中含有三种具有精氨酸酯酶活力的组分。它们分别是激肽释放酶、类凝血酶及类溶血纤维酶。其中类凝血酶的精氨酸酯酶活力最高,约占总酯酶活力的60%。(2) 提纯后的类凝血酶在聚丙烯酰胺凝胶电泳上呈一条区带。经凝胶过滤及SDS聚丙烯酰胺凝胶电泳测定,其分子量约43,000。氨基酸组成分析表明含有较多的酸性氨基酸及脯氨酸,此外还含有约6%的中性糖,9%的己糖胺及3.3%的唾液酸。(3) 类凝血酶能直接使血纤维蛋白原凝聚,水解BAEE的活力约是胰蛋白酶的2.7倍,K_m为3.4×10~(-4)M,高于其它已知的蝮亚科蛇毒类凝血酶活力。它不作用于BANA、BAPA及其它蛋白底物。蛇毒类凝血酶与人凝血酶一样,对专一萤光底物Boc-Val-Pro-Arg-MCA都有明显活力,但其凝结血纤维蛋白原的活力却远低于人凝血酶。(4) 类凝血酶能被DFP及PMSF所抑制,但抑制速度缓慢,不能被胰蛋白酶的专一抑制剂TLCK所抑制,因而是专一性很强的丝氨酸蛋白酶。     

烙铁头蛇毒纤维蛋白原溶酶研究——Ⅱ.对纤维蛋白原及凝血酶的作用

烙铁头(T.mucrosquamatus)蛇毒纤维蛋白原溶酶TMVFg能水解三肽底物Bz-Phe-Val-Arg-PNA,但对凝血酶的良好底物Cbz-Gly-Pro-Arg-PNA却活性甚低。TMVFS显著延长血浆凝血酶时间。血浆复钙时间及纤维蛋白原溶液凝血酶时间。同时,TMVFg体外也能延长全血凝固时间,表明具有抗凝作用。纤维蛋白原-纤维蛋白转换实验表明:TMVFg水解纤维蛋白原产生的纤维蛋白原断片(FDP)除具有抗凝血酶,抑制纤维蛋白聚合活性外,还能促进纤维蛋白的聚合。 进一步用FPLC分离TMVFg水解人纤维蛋白原混合液,得两个FDP断片功能峰,FDP组分Ⅰ和FDP组分Ⅱ。其中FDP组分Ⅰ能抑制纤维蛋白凝块形成;FDP组分Ⅱ能促进纤维蛋白凝块形成,抑制TMVA(烙铁头蛇毒血小板活化素,它可不通过ADP、花生四烯酸途径而诱导血小板聚集),但对ADP诱导的家兔血小板聚集无影响。TMVFg对凝血酶水解三肽底物Cbz-Gly-Pro-Arg-PNA及凝固纤维蛋白原的活性也有一定抑制作用。 实验证明,TMVFg抗凝的主要作用机理是其水解纤维蛋白原产生的断片对纤维蛋白原凝固的抑制作用、FDP断片抗凝血酶作用及TMVFg本身对凝血酶活性的抑制所引起的,但在二者之间,前者是主要的。 从研究结果发现:TMVFg水解纤维蛋白原所产生的断片有一类能加速凝血酶凝固纤维蛋白原的过程,这就发现了FDP断片的     

蝮蛇(Agkistrodon halys Palls)蛇毒类凝血酶的研究——Ⅱ.类凝血酶对纤维蛋白原的作用方式

许多蝮亚科蛇毒中含有类凝血酶。它们和蛇伤引起的毒理作用有密切关系。由于它对纤维蛋白原的作用特点,在临床上已被用作抗凝剂治疗血管阻塞性疾病。此外,它也被用来研究纤维蛋白的聚合机制。     

蝮蛇(Agkistrodon halys Pallas)蛇毒类凝血酶的研究——Ⅱ.类凝血酶对纤维蛋白原的作用方式

许多蝮亚科蛇毒中含有类凝血酶。它们和蛇伤引起的毒理作用有密切关系。由于它对纤维蛋白原的作用特点,在临床上已被用作抗凝剂治疗血管阻塞性疾病。此外,它也被用来研究纤维蛋白的聚合机制。     

蛇毒类凝血酶的研究进展

蛇毒类凝血酶（TLE）属胰蛋白酶家族中的丝氨酸蛋白酶,在序列上与胰蛋白酶有更多的保守序列。具有精氨酸酯酶活性,能直接作用于纤维蛋白原,催化纤维蛋白原分子的特定部位Arg—Gly肽键的裂解,释放血纤肽A（FPA）或B（FPB）,导致纤维蛋白的单体首尾聚合而凝固,故被称为类凝血酶。但它在体内不激活凝血因子瑚,由它水解生成的纤维蛋白凝块不产生侧链交联,对纤溶酶的消化高度敏感,易被天然网状内皮系统或正常的纤溶作用所清除。因此导致胞浆中纤维蛋白原浓度显著下降,表现降纤、抗凝的效果。     

蛇毒凝血酶原激活组分的研究概况

<正>蛇毒是一类复杂的具有多种生物学活性的蛋白质和蛋白多肽。目前已经分离纯化出许多作用于血液凝固酶促级联反应过程中的一个或多个环节的蛇毒组分,包括FⅡ、FⅤ、FⅦ、FⅩ等激活剂以及直接使纤维蛋白原凝聚的蛇毒凝血酶样酶。蛇毒蛋白中有一类凝血毒素作用于血液凝固酶促级联反应,发挥止血作用,作用方式:(1)激活内源性和外源性凝血途径中的各种凝血因子,从而促进血液凝固。(2)激活凝血酶原,从而发挥凝血作用。(3)直接使纤维蛋白原变成纤维蛋白,即类似凝血酶样作用[1]。现已在临床上广泛     

On the origin of the Hirudinea and the demise of the Oligochaeta

The phylogenetic relationships of the Clitellata were investigated with a data set of published and new complete 18S rRNA gene sequences of 51 species representing 41 families. Sequences were aligned on the basis of a secondary structure model and analysed with maximum parsimony and maximum likelihood. In contrast to the latter method, parsimony did not recover the monophyly of Clitellata. However, a close scrutiny of the data suggested a spurious attraction between some polychaetes and clitellates. As a rule, molecular trees are closely aligned with morphology-based phylogenies. Acanthobdellida and Euhirudinea were reconciled in their traditional Hirudinea clade and were included in the Oligochaeta with the Branchiobdellida via the Lumbriculidae as a possible link between the two assemblages. While the 18S gene yielded a meaningful historical signal for determining relationships within clitellates, the exact position of Hirudinea and Branchiobdellida within oligochaetes remained unresolved. The lack of phylogenetic signal is interpreted as evidence for a rapid radiation of these taxa. The placement of Clitellata within the Polychaeta remained unresolved. The biological reality of polytomies within annelids is suggested and supports the hypothesis of an extremely ancient radiation of polychaetes and emergence of clitellates.     

On the ontogeny of the haptor and the evolution of the Monogenea

Data on the ontogeny of the posterior haptor of monogeneans were obtained from more than 150 publications and summarised. These data were plotted into diagrams showing evolutionary capacity levels based on the theory of a progressive evolution of marginal hooks, anchors and other attachment components of the posterior haptor in the Monogenea (Malmberg, 1986). 5 + 5 unhinged marginal hooks are assumed to be the most primitive monogenean haptoral condition. Thus the diagrams were founded on a 5 + 5 unhinged marginal hook evolutionary capacity level, and the evolutionary capacity levels of anchors and other haptoral attachement components were arranged according to haptoral ontogenetical sequences. In the final plotting diagram data on hosts, type of spermatozoa, oncomiracidial ciliation, sensilla pattern and protonephridial systems were also included. In this way a number of correlations were revealed. Thus, for example, the number of 5 + 5 marginal hooks correlates with the most primitive monogenean type of spermatozoon and with few sensillae, many ciliated cells and a simple protonephridial system in the oncomiracidium. On the basis of the reviewed data it is concluded that the ancient monogeneans with 5 + 5 unhinged marginal hooks were divided into two main lines, one retaining unhinged marginal hooks and the other evolving hinged marginal hooks. Both main lines have recent representatives at different marginal hook evolutionary capacity levels, i.e. monogeneans retaining a haptor with only marginal hooks. For the main line with hinged marginal hooks the name Articulon-choinea n. subclass is proposed. Members with 8 + 8 hinged marginal hooks only are here called Proanchorea n. superord. Monogeneans with unhinged marginal hooks only are here called Ananchorea n. superord. and three new families are erected for its recent members: Anonchohapteridae n. fam., Acolpentronidae n. fam. and Anacanthoridae n. fam. (with 7 + 7, 8 + 8 and 9 + 9 unhinged marginal hooks, respectively). Except for the families of Articulonchoinea (e.g. Acanthocotylidae, Gyrodactylidae, Tetraonchoididae) Bychowsky's (1957) division of the Monogenea into the Oligonchoinea and Polyonchoinea fits the proposed scheme, i.e. monogeneans with unhinged marginal hooks form one old group, the Oligonchoinea, which have 5 + 5 unhinged marginal hooks, and the other group form the Polyonchoinea, which (with the exception of the Hexabothriidae) has a greater number (7 + 7, 8 + 8 or 9 + 9) of unhinged marginal hooks. It is proposed that both these names, Oligonchoinea (sensu mihi) and Polyonchoinea (sensu mihi), will be retained on one side and Articulonchoinea placed on the other side, which reflects the early monogenean evolution. Except for the members of Ananchorea [Polyonchoinea], all members of the Oligonchoinea and Polyonchoinea have anchors, which imply that they are further evolved, i.e. have passed the 5 + 5 marginal hook evolutionary capacity level (Malmberg, 1986). There are two main types of anchors in the Monogenea: haptoral anchors, with anlages appearing in the haptor, and peduncular anchors, with anlages in the peduncle. There are two types of haptoral anchors: peripheral haptoral anchors, ontogenetically the oldest, and central haptoral anchors. Peduncular anchors, in turn, are ontogenetically younger than peripheral haptoral anchors. There may be two pairs of peduncular anchors: medial peduncular anchors, ontogentically the oldest, and lateral peduncular anchors. Only peduncular (not haptoral) anchors have anchor bars. Monogeneans with haptoral anchors are here called Mediohaptanchorea n. superord. and Laterohaptanchorea n. superord. or haptanchoreans. All oligonchoineans and the oldest polyonchoineans are haptanchoreans. Certain members of Calceostomatidae [Polyonchoinea] are the only monogeneans with both (peripheral) haptoral and peduncular anchors (one pair). These monogeneans are here called Mixanchorea n. superord. Polyonchoineans with peduncular anchors and unhinged marginal hooks are here called the Pedunculanchorea n. superord. The most primitive pedunculanchoreans have only one pair of peduncular anchors with an anchor bar, while the most advanced have both medial and lateral peduncular anchors; each pair having an anchor bar. Certain families of the Articulonchoinea, the Anchorea n. superord., also have peduncular anchors (parallel evolution): only one family, the Sundanonchidae n. fam., has both medial and lateral peduncular anchors, each anchor pair with an anchor bar. Evolutionary lines from different monogenean evolutionary capacity levels are discussed and a new system of classification for the Monogenea is proposed.In agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. EditorIn agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. Editor