Enzyme 6-phosphofructo-1-kinase is an important regulatory enzyme of glycolysis. There are three types of this enzyme and the liver type, Pfk-L, was found in higher concentrations in human cancer cells. A known characteristic of Pfk-L is a posttranslational modification which results in a shorter, but a more active isoform of the enzyme. We inserted genes for both isoforms of the enzyme in a plasmid, and the plasmids were inserted in a Pfk-null yeast strain. We grew both strains in a medium without uracil, to confirm the presence of the plasmid in the cells. Then, we grew those two strains with other control strains on solid and in liquid media. These media had as a source of carbon different sugars: glucose, fructose or maltose. Transformed strains grew best on solid media with maltose and in liquid media with maltose and ethanol. This was probably due to fact that the inserted genes could not be translated and/or folded into an active form of the enzyme. Minimal activity was also confirmed with an experiment where we measured only PFK-L enzyme activity. Since even the native form of the enzyme could not enable growth on glucose or fructose, we concluded that the selected gene was not the best option, because it was not the canonical one.
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