Oikarinen A, Anttinen H, Kivirikko K I
Biochem J. 1977 Sep 15;166(3):357-62. doi: 10.1042/bj1660357.
The hydroxylation of lysine and glycosylations of hydroxylysine were studied in isolated chick-embryo tendon and cartilage cells under conditions in which collagen triple-helix formation was either inhibited or accelerated. The former situation was obtained by incubating the tendon cells with 0.6mm-dithiothreitol, thus decreasing their proline hydroxylase activity by about 99%. After labelling with [(14)C]proline, the formation of hydroxy[(14)C]proline was found to have declined by about 95%. Since the hydroxylation of a relatively large number of proline residues is required for triple-helix formation at 37 degrees C, the pro-alpha-chains synthesized under these conditions apparently cannot form triple-helical molecules. Labelling experiments with [(14)C]lysine indicated that the degree of hydroxylation of the lysine residues in the collagen synthesized was slightly increased and the degree of the glycosylations of the hydroxylysine residues more than doubled, the largest increase being in the content of glucosylgalactosylhydroxylysine. Recovery of chick-embryo cartilage cells from temporary anoxia was used to obtain accelerated triple-helix formation. A marked decrease was found in the extent of hydroxylation of the lysine residues in the collagen synthesized under these conditions, and an even larger decrease occurred in the glycosylations of the hydroxylysine residues. The results support the previous suggestion that the triple-helix formation of the pro-alpha-chains prevents further hydroxylation of lysine residues and glycosylations of hydroxylysine residues during collagen biosynthesis.
在胶原三螺旋形成被抑制或加速的条件下，对分离的鸡胚肌腱和软骨细胞中赖氨酸的羟基化和羟赖氨酸的糖基化进行了研究。前一种情况是通过用0.6mmol/L二硫苏糖醇孵育肌腱细胞来实现的，从而使其脯氨酸羟化酶活性降低约99%。用[(14)C]脯氨酸标记后，发现羟[(14)C]脯氨酸的形成下降了约95%。由于在37℃下形成三螺旋需要相当数量的脯氨酸残基被羟基化，因此在这些条件下合成的原α链显然不能形成三螺旋分子。用[(14)C]赖氨酸进行的标记实验表明，合成的胶原中赖氨酸残基的羟基化程度略有增加，羟赖氨酸残基的糖基化程度增加了一倍多，最大的增加是葡萄糖基半乳糖基羟赖氨酸的含量。利用鸡胚软骨细胞从短暂缺氧中恢复来实现加速的三螺旋形成。发现在这些条件下合成的胶原中赖氨酸残基的羟基化程度显著降低，羟赖氨酸残基的糖基化程度下降得更大。这些结果支持了先前的推测，即在胶原生物合成过程中，原α链的三螺旋形成会阻止赖氨酸残基的进一步羟基化和羟赖氨酸残基的糖基化。
