多价金属离子对溶菌酶的抑制作用。

Inhibition of lysozyme by polyvalent metal ions.

作者信息

Ostroy F, Gams R A, Glickson J D, Lenkinski R E

出版信息

Biochim Biophys Acta. 1978 Nov 10;527(1):56-62. doi: 10.1016/0005-2744(78)90255-3.

Abstract

The rate of hen egg-white lysozyme (mucopeptide N-acetylmuramoylhydrolase, EC 3.2.1.17), catalysis was determined in the presence of various metal ions (Co2+, Zn2+ and eight of the trivalent lanthanide ions). In the assay system employed, the lanthanides were found to inhibit more strongly than either Zn2+ or Co2+. The inhibition data was fitted to several models of the interactions of the metal ion with the enzyme. These models ranged in complexity from a single inhibitory metal binding site on the enzyme (two-parameter fit) to the presence of two non-independent and non-equivalent inhibitory metal binding sites (five-parameter fit). The more complicated models did not fit the data more precisely than the simplest one-site model, suggesting that the adoption of the simpler model is warranted. The fact that the association constants obtained from the simplest analysis for Co2+ (1.3 +/- 1.9 . 10(2) M-1) and Gd3+ (7.0 +/- 2.6 . 10(3) M-1) are consistent with literature values determined from spectroscopic measurements further supports the validity of the simplest model.

摘要

在存在各种金属离子（Co²⁺、Zn²⁺和八种三价镧系离子）的情况下，测定了鸡蛋清溶菌酶（粘肽N - 乙酰胞壁酰水解酶，EC 3.2.1.17）的催化速率。在所采用的测定系统中，发现镧系离子的抑制作用比Zn²⁺或Co²⁺更强。将抑制数据拟合到金属离子与酶相互作用的几种模型中。这些模型的复杂程度从酶上的单个抑制性金属结合位点（双参数拟合）到存在两个非独立且不等价的抑制性金属结合位点（五参数拟合）不等。更复杂的模型并不比最简单的单一位点模型更精确地拟合数据，这表明采用更简单的模型是合理的。从对Co²⁺（1.3 ± 1.9·10² M⁻¹）和Gd³⁺（7.0 ± 2.6·10³ M⁻¹）的最简单分析中获得的缔合常数与通过光谱测量确定的文献值一致，这进一步支持了最简单模型的有效性。