Puistola U, Anttinen H
Biochim Biophys Acta. 1982 Jul 16;717(1):118-23. doi: 10.1016/0304-4165(82)90388-9.
Various chick embryo tissues were incubated in vitro with a range of Zn2+ concentrations, and inhibition of the hydroxylations of collagen proline and lysine residues was studied in the intact tissues. At an constant inhibition level of proline hydroxylation, lysine hydroxylation proved to be inhibited more in the skin and bone than in the tendon and cartilage. The ratios of lysyl hydroxylase to prolyl hydroxylase activity were also distinctly lower in the former than in the latter. The variations observed in the reduction of lysine hydroxylation by Zn2+ thus correlate well with the differences seen in the enzyme activity ratios. No differences are found in the Ki values for Zn2+ between purified prolyl and lysyl hydroxylases or between the same enzymes from different tissues, and consequently the differences in lysine hydroxylation inhibition between the various tissues cannot be explained by differences in the kinetic constants. Recent studies also suggest that the existence of tissue-specific lysyl hydroxylase isoenzymes is improbable. The data thus suggest that there is a relative excess of lysyl hydroxylase activity in tissues such as tendon and cartilage, in which the lysine hydroxylation was less sensitive to Zn2+ inhibition, compared with skin and bone, where lysine hydroxylation was inhibited to a greater extent. These data are in a good agreement with the findings concerning variation in the reduction in lysine hydroxylation in different tissues with age or in the Ehlers-Danlos Syndrome Type VI.
将各种鸡胚组织在体外与一系列不同浓度的Zn2+一起孵育，并在完整组织中研究胶原脯氨酸和赖氨酸残基羟基化的抑制情况。在脯氨酸羟基化的抑制水平恒定的情况下，皮肤和骨骼中赖氨酸羟基化的抑制程度比肌腱和软骨中更大。前者中赖氨酰羟化酶与脯氨酰羟化酶活性的比率也明显低于后者。因此，观察到的Zn2+对赖氨酸羟基化的抑制差异与酶活性比率的差异密切相关。纯化的脯氨酰羟化酶和赖氨酰羟化酶之间或来自不同组织的相同酶之间，Zn2+的Ki值没有差异，因此，不同组织之间赖氨酸羟基化抑制的差异不能用动力学常数的差异来解释。最近的研究还表明，组织特异性赖氨酰羟化酶同工酶不太可能存在。这些数据表明，与赖氨酸羟基化受到更大抑制的皮肤和骨骼相比，在肌腱和软骨等组织中，存在相对过量的赖氨酰羟化酶活性，其中赖氨酸羟基化对Zn2+抑制不太敏感。这些数据与不同组织中赖氨酸羟基化随年龄变化或在VI型埃勒斯-当洛综合征中的变化结果非常一致。
