Barnes M J, Constable B J, Morton L F, Royce P M
Biochem J. 1974 May;139(2):461-8. doi: 10.1042/bj1390461.
The effect of age on the extent of hydroxylation of lysine and proline both generally and at certain specific sites in collagens from bone, skin and tendon was examined in the chick from the 14-day embryo to the 18-month-old adult. For all collagens there was a marked fall in the overall extent of hydroxylation of lysine with increasing age in both alpha(1) and alpha(2) chains, this fall occurring mostly in a relatively short period immediately after hatching. Hydroxylation of lysine declined to a constant value which, as expected, differed appreciably for each collagen and was considered to be characteristic of the collagen according to its tissue of origin. Hydroxylation of lysine in the N-terminal, non-helical telopeptide region of both alpha(1) and alpha(2) chains, which is important with regard to cross-linking, was relatively high in embryonic collagens. There was, however, a rapid loss of hydroxylation at these sites in skin collagen, occurring both during development of the embryo and in the period immediately after hatching. In contrast some hydroxylation at these sites persisted in bone and tendon collagens and, as judged by examination of peptide alpha(1)-CB1, appeared to reach a constant value in time of about 33% in bone and about 15% in tendon collagen. The actual extent of hydroxylation of lysine in the N-terminal telopeptides and the size of the changes in these values with age appeared to be unrelated to the corresponding whole-chain values, and it is suggested therefore that hydroxylation of telopeptidyl lysine may be under separate enzymic control. The increased hydroxylation of lysine in the embryo was accompanied by only minimal changes in proline hydroxylation, which was very slightly increased in embryonic bone and tendon collagens. Increased hydroxylation of proline in the embryo was, however, readily observed in peptide alpha(1)-CB2 from the helical region of tendon collagen. This hydroxylation was close to the theoretical maximum, in contrast with that observed in post-embryonic tendon, where hydroxylation was incomplete, as in rat tendon (Bornstein, 1967), only four on average, of the six susceptible proline residues being hydroxylated.
研究了从14天胚胎期到18个月成年期的雏鸡中，年龄对赖氨酸和脯氨酸羟基化程度的影响，包括总体影响以及在来自骨骼、皮肤和肌腱的胶原蛋白中某些特定位点的影响。对于所有胶原蛋白，随着年龄增长，α(1)链和α(2)链中赖氨酸的总体羟基化程度均显著下降，这种下降主要发生在孵化后的相对短时间内。赖氨酸的羟基化程度下降至一个恒定值，正如预期的那样，每种胶原蛋白的该值明显不同，并被认为是根据其来源组织的胶原蛋白的特征。α(1)链和α(2)链的N端非螺旋端肽区域中赖氨酸的羟基化，在交联方面很重要，在胚胎胶原蛋白中相对较高。然而，在皮肤胶原蛋白中，这些位点的羟基化在胚胎发育期间和孵化后的一段时间内迅速丧失。相比之下，这些位点在骨骼和肌腱胶原蛋白中仍有一些羟基化，通过对肽α(1)-CB1的检测判断，在骨骼中似乎在约33%的时间达到恒定值，在肌腱胶原蛋白中约为15%。N端端肽中赖氨酸的实际羟基化程度以及这些值随年龄的变化大小，似乎与相应的整条链的值无关，因此表明端肽赖氨酸的羟基化可能受单独的酶控制。胚胎中赖氨酸羟基化增加的同时，脯氨酸羟基化仅有最小变化，在胚胎骨骼和肌腱胶原蛋白中略有增加。然而，在来自肌腱胶原蛋白螺旋区域的肽α(1)-CB2中很容易观察到胚胎中脯氨酸羟基化增加。这种羟基化接近理论最大值，与胚胎后肌腱中观察到的情况形成对比，在胚胎后肌腱中，羟基化不完全，如在大鼠肌腱中（伯恩斯坦，1967年），六个易被羟基化的脯氨酸残基平均只有四个被羟基化。
