Kagan H M, Reddy V B, Narasimhan N, Csiszar K
Department of Biochemistry, Boston University School of Medicine, MA 02118, USA.
Ciba Found Symp. 1995;192:100-15; discussion 115-21. doi: 10.1002/9780470514771.ch6.
Key aspects of the biosynthesis and catalytic specificity of lysyl oxidase (LO) have been explored. Oxidation of peptidyl lysine in synthetic oligopeptides is markedly sensitive to the presence of vicinal dicarboxylic ami/no acid residues. Optimal activity is obtained with the -Glu-Lys- sequence within a polyglycine 11-mer, whereas the -Lys-Glu- sequence is much less efficiently oxidized. The -Asp-Glu-Lys- sequence is a very poor substrate, although this sequence is oxidized in type I collagen fibrils. These results are considered in the light of a model requiring collagen to be assembled as fibrils prior to oxidation by LO. An in vitro system for the expression of catalytically active LO has been devised. Deletion or inclusion of the cDNA coding for the propeptide region in the expressed construct results in apparently identical, catalytically active enzyme products, indicating the lack of essentiality of this region for active enzyme production. These effects are considered with respect to the conservation of the amino acid sequence of LO produced by different species.
已对赖氨酰氧化酶（LO）的生物合成及催化特异性的关键方面进行了探究。合成寡肽中肽基赖氨酸的氧化对相邻二羧酸氨基酸残基的存在极为敏感。在聚甘氨酸11聚体中，-Glu-Lys-序列可获得最佳活性，而-Lys-Glu-序列的氧化效率则低得多。-Asp-Glu-Lys-序列是一种非常差的底物，尽管该序列在I型胶原纤维中会被氧化。这些结果是根据一种模型来考虑的，该模型要求胶原蛋白在被LO氧化之前先组装成纤维。已设计出一种用于表达具有催化活性的LO的体外系统。在表达构建体中缺失或包含编码前肽区的cDNA会产生明显相同的、具有催化活性的酶产物，这表明该区域对于产生活性酶并非必不可少。结合不同物种产生的LO的氨基酸序列保守性来考虑这些效应。
