Monooksygenaza metanowa - występowanie, właściwości oraz perspektywy wykorzystania w procesach biotechnologicznych

Na stronie 75 dodano "Nowości" - "Tytoń odporny na herbicydy"

In all methylotrophs studies so far, methane is oxidized to methanol by means of a monooxygenase. Two monooxygenase systems have so far been identified, soluble and particulate. The most extensively characterized one Is a soluble NADH- dependent system In Methylococcus capsulatus (Bath). The enzyme comprises three proteins: A, B, C. Protein A has MW of 220 000 and contains non - beam iron, the reduced form of which may be responsible for binding methane. It contains three types of subunits: alpha, beta and gamma with MW values respectively 54 000, 36 000, 17 000 arranged with the stoichiometry ocg p2 Ya- Subunit B is colourless protein of MW 17 000. The protein B plays a regulatory function; it converts the combination of protein A and C from NADH oxidase activity to monooxygenase activity and makes the electron transfer process dependent on methane or another hydroxylatable substrate. Protein C, MW 42 000, containing FAD as well as sulphur iron cluster, oxidizes NADH using either A and hence methanol or alternatively electron acceptors such as 2,6 dichlorophenol-Indo-phenol or cytochrome C as electron acceptor. The whole complex is required for hydroxylation of methane. Some biotechnological aspects using methylotrophs are disccused. Perhaps the most valuable biotransformations catalysed by MMO are in the production of epoxides e.g. propylene oxide from propylene.