Gauthier F, Gutman N, Moreau T, el Moujahed A
Université François Rabelais, Laboratoire de Biochimie, Faculté de Médecine, Tours, France.
Biol Chem Hoppe Seyler. 1988 May;369 Suppl:251-5.
Studies on biological properties of rat T kininogen have shown that the role of this peculiar kininogen so far specific to the rat probably differs significantly from that of other low molecular mass kininogens. In particular the kinin precursor function has been either lost or considerably reduced as a result of structural modifications during evolution. The calpain inhibiting function demonstrated for other low and high molecular mass kininogens has also probably disappeared from T kininogen, and since T genes do not allow the synthesis of high molecular mass kininogens [Kitagawa et al. (1987) J. Biol. Chem. 262, 2190-2198], the procoagulant function devoted to the light chain of high molecular mass kininogen has also been lost by T genes products. The only remaining function of rat T kininogen would be therefore that of a lysosomal cysteine proteinase inhibitor which is expressed either by the native molecule or by proteolytic products which appear to be more easily released than vasoactive peptides. Such a specialization for a given function could be related to the behaviour of T kininogen as an acute phase reactant, the dramatic changes in concentration of which could at the same time serve certain functions and be damageable for others.
对大鼠T激肽原生物学特性的研究表明，这种迄今为止仅在大鼠中存在的特殊激肽原，其作用可能与其他低分子量激肽原存在显著差异。特别是，由于进化过程中的结构修饰，激肽前体功能要么已经丧失，要么大幅降低。其他低分子量和高分子量激肽原所具有的钙蛋白酶抑制功能，在T激肽原中可能也已消失。而且，由于T基因无法合成高分子量激肽原[北川等人（1987年）《生物化学杂志》262卷，2190 - 2198页]，高分子量激肽原轻链所具有的促凝血功能在T基因产物中也已丧失。因此，大鼠T激肽原仅存的功能可能是作为一种溶酶体半胱氨酸蛋白酶抑制剂，它可由天然分子表达，也可由似乎比血管活性肽更容易释放的蛋白水解产物表达。这种针对特定功能的特化可能与T激肽原作为急性期反应物的行为有关，其浓度的急剧变化可能在为某些功能服务的同时，对其他功能造成损害。
