Kinetics for the secretion of procollagen by freshly isolated tendon cells.
Kinetics for the secretion of procollagen by freshly isolated tendon cells.
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新鲜分离的肌腱细胞分泌前胶原的动力学。
DOI：
10.1016/s0021-9258(19)75231-4
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发表时间：
1977
期刊：
影响因子：
--
通讯作者：
D. Prockop
中科院分区：
文献类型：
--
作者：
W. Kao;R. Berg;D. Prockop
用酶消化法分离鸡胚腱成纤维细胞，在处于稳定状态的条件下悬浮培养数小时，以合成和分泌前胶原。在此条件下，细胞合成和分泌约630微克的前胶原/10(9)个/h，用[14C]Pro标记细胞15~120min，然后追踪标记，测定细胞内和培养上清液中胶原酶可消化的14C-肽的分泌动力学。结果表明，胶原酶可消化肽的分泌不遵循单一的一级动力学过程，而是至少两个准一级过程，半衰期分别为14和115min。在0~30min和90~120min的Chase中分泌的[14C]前胶原在前-α1/前α2链的比例、前-α链的大小、链间二硫键结合的程度、脯氨酸羟化的程度以及抗胃酶消化试验的螺旋度方面是相同的。在培养液中加入抗坏血酸，可轻微增加细胞内Pro羟化的程度，但不改变细胞分泌的动力学。结果表明，分泌的动力学受到一个两室系统的影响，在这个系统中，至少有一个有助于分泌过程的代谢池存在于“侧袋”中。
Fibroblasts isolated by enzymic digestion of chick embryo tendons were incubated for several hours in suspension under conditions in which they were in steady state in terms of the synthesis and secretion of procollagen. Under these conditions, the cells synthesized and secreted about 630 microgram of procollagen/10(9) cells/h. The cells were labeled with [14C]proline for 15 to 120 min and then the kinetics of secretion were followed by chasing the label and assaying the 14C-peptides digestible by collagenase in the cells and in the medium. The results demonstrated that secretion of collagenase-digestible peptides did not follow the kinetics of a single first order process but suggested at least two pseudo-first order process with half-times of 14 and 115 min. The [14C]procollagen secreted during 0 to 30 min and 90 to 120 min of chase was the same in terms of the ratio of pro-alpha1 to pro-alpha2 chains, the size of the pro-alpha chains, the extent of interchain disulfide bonding, the extent of prolyl hydroxylation, and the degree of helicity as tested by resistance to pepsin digestion. Addition of ascorbic acid to the incubation medium increased slightly the extent of prolyl hydroxylation but did not alter the kinetics of secretion. The results suggested that the kinetics of secretion are influenced by a two-compartment system in which at least one metabolic pool contributing to the secretory process is present as a “side pocket.”