Kinetics for the secretion of nonhelical procollagen by freshly isolated tendon cells.
Kinetics for the secretion of nonhelical procollagen by freshly isolated tendon cells.
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新鲜分离的肌腱细胞分泌非螺旋前胶原的动力学。
DOI：
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发表时间：
1979
影响因子：
4.8
通讯作者：
R. Berg
中科院分区：
文献类型：
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作者：
W. Kao;D. Prockop;R. Berg
通过酶消化鸡胚腱分离的成纤维细胞以前曾被用来研究前胶原的分泌动力学(Kao，W.W.-Y.，Berg，R.A.，和Proockop，D.J.(1977)J.Biol)。化学。252、8391-8397)。结果表明，反应动力学近似为两个一级过程之和，半衰期分别为14和115min。在此，同样的成纤维细胞在1.53 mM的顺式-4-羟基脯氨酸或0.3 mM的α，α‘-联吡啶或0.3 mM的α，α’-联吡啶的存在下孵育，以使细胞合成的前胶原不能呈现前胶原的三螺旋构象特征。对非螺旋型前胶原分泌的测定表明，其分泌动力学不同于前胶原的分泌动力学，近似为一级过程，半衰期约为130min。在顺式-4-羟基脯氨酸或α，α‘-联吡啶存在下合成和分泌的非螺旋前胶原由I型前胶原的二硫键前伽马链组成。结果表明，细胞内的非螺旋前胶原存在于单个代谢池中，从该代谢池中分泌的速度限制步骤与螺旋前胶原不同。进一步的结果表明，非螺旋前胶原对Pro羟基酶有很高的亲和力，如果允许前胶原呈现正常前胶原的三螺旋构象特征，则对该酶的亲和力会大大降低。这一结果与前胶原蛋白的分泌受其与Pro羟基酶或其他翻译后酶构象依赖的相互作用的影响的假说是一致的。
Fibroblasts isolated by enzymic digestion of chick embryo tendons have previously been used to examine the kinetics for the secretion of procollagen (Kao, W. W.-Y., Berg, R. A., and Prockop, D. J. (1977) J. Biol. Chem. 252, 8391-8397). The results indicated that the kinetics approximated the sum of two first order processes with half-times of 14 and 115 min. Here, the same fibroblasts were incubated in the presence of 1.53 mM cis-4-hydroxyproline, an analogue of proline, or in the presence of 0.3 mM alpha,alpha'-dipyridyl, an inhibitor of prolyl hydroxylase, so that the cells synthesized procollagen which could not assume a triple helical conformation characteristic of procollagen. Measurements of the secretion of nonhelical procollagen indicated that the kinetics for secretion differed from the kinetics for the secretion of procollagen and approximated a single first order process with a half-time of approximately 130 min. The nonhelical procollagen synthesized and secreted in the presence of either cis-4-hydroxyproline or alpha,alpha'-dipyridyl consisted of disulfide-bonded pro gamma chains of type I procollagen. The results suggested that the intracellular nonhelical procollagen was present in a single metabolic pool and secretion from this pool occurred with a different rate-limiting step than for helical procollagen. Further results indicated that nonhelical procollagen had a high affinity for prolyl hydroxylase and the affinity for the enzyme was greatly reduced if the procollagen was allowed to assume the triple helical conformation characteristic of normal procollagen. The results are consistent with the hypothesis that the secretion of procollagen is influenced by its conformation-dependent interaction with prolyl hydroxylase or other post-translational enzymes.