Green J, Prior S D, Dalton H
Eur J Biochem. 1985 Nov 15;153(1):137-44. doi: 10.1111/j.1432-1033.1985.tb09279.x.
Copper(I), copper(II) and silver ions have been shown to be potent inhibitors of purified soluble methane monooxygenase (MMO) of Methylococcus capsulatus (Bath). A weaker inhibition has been observed with zinc and cadmium ions. Proteins A and B of soluble MMO are unaffected by copper but protein C is rapidly and irreversibly inhibited. The site of copper inhibition has been shown to be primarily at the iron-sulphur centre of protein C with a secondary effect at the FAD centre when the copper(II):protein C ratio is high. Copper appears to bring about the inhibition of soluble MMO by interacting with protein C to disrupt the protein structure causing, firstly, the loss of the iron-sulphur centre, preventing the transfer of electrons from protein C to protein A, and secondly, the loss of FAD preventing the protein from accepting electrons from NADH. Inhibition and spectral data are provided to support this thesis. The inactivation of protein C is associated with the tight binding of four Cu atoms to each protein C molecule. These data extend our knowledge of how copper, which is known to have a key role in the cellular location of MMO, interacts with and rapidly and irreversibly inactivates the soluble form of this enzyme.
已证明，铜（I）、铜（II）和银离子是甲基球菌（巴斯德）纯化的可溶性甲烷单加氧酶（MMO）的有效抑制剂。锌和镉离子的抑制作用较弱。可溶性MMO的蛋白质A和B不受铜的影响，但蛋白质C会被迅速且不可逆地抑制。已证明，铜抑制的位点主要在蛋白质C的铁硫中心，当铜（II）与蛋白质C的比例较高时，对FAD中心有次要影响。铜似乎通过与蛋白质C相互作用来抑制可溶性MMO，破坏蛋白质结构，首先导致铁硫中心的丧失，阻止电子从蛋白质C转移到蛋白质A，其次导致FAD的丧失，阻止蛋白质从NADH接受电子。提供了抑制和光谱数据来支持这一论点。蛋白质C的失活与四个铜原子与每个蛋白质C分子的紧密结合有关。这些数据扩展了我们对铜的认识，已知铜在MMO的细胞定位中起关键作用，它如何与这种酶的可溶性形式相互作用并使其迅速且不可逆地失活。
