Gorlatova N V, Kriukova E G
Mikrobiologiia. 1994 May-Jun;63(3):450-6.
As is shown expression homologous (dihydroxyacetone kinase) and heterologous (HBsAg, beta-galactosidase) genes in methylotrophic yeasts Hansenula polymorpha DL1 negatively affects on the growth parameters of a host strain. The reducing of specific growth rate (mu max) and yield of biomass per the unit of a consumed substrate (Yx/s) were found in all recombinant strains grown on methanol. Overproduction of dihydroxyacetone kinase and beta-galactosidase in recombinant H. polymorpha was accompanied by two-fold increasing of the activity of alcohol oxidase, which is the first enzyme of methanol oxidation. Otherwise, the activity of formaldehyde dehydrogenase two-fold decreased in the recombinant strain overproducing HBsAg compared with the host strain. It is suggested that the over-synthesis of foreign proteins requiring an additional energetic and metabolic expenses might reduce the growth parameters and the activities of some enzymes of methanol metabolism in recombinant methylotrophic yeast H. polymorpha.
如图所示，在多形汉逊酵母Hansenula polymorpha DL1中表达同源（二羟基丙酮激酶）和异源（乙肝表面抗原、β-半乳糖苷酶）基因会对宿主菌株的生长参数产生负面影响。在以甲醇为培养基生长的所有重组菌株中，均发现其比生长速率（μmax）降低，单位消耗底物的生物量产量（Yx/s）减少。重组多形汉逊酵母中二羟基丙酮激酶和β-半乳糖苷酶的过量表达伴随着甲醇氧化的首个酶——乙醇氧化酶活性增加两倍。此外，与宿主菌株相比，过量表达乙肝表面抗原的重组菌株中甲醛脱氢酶的活性降低了两倍。这表明，在重组多形汉逊酵母中，需要额外能量和代谢消耗的外源蛋白的过量合成可能会降低生长参数以及甲醇代谢某些酶的活性。
