An Autoinhibitory Domain Confers Redox Regulation to Maize Glycerate Kinase - Essay Example

This paper summarizes the article of Bartsch, Mikkat, Hagemann, and Bauwe, en d An Autoinhibitory Domain Confers Redox Regulation to Maize Glycerate Kinase (Plant Physiology, 2010, vol. 153, pp. 832-840). They wanted to know the molecular mechanisms that regulate the activity of their glycerate kinase (GLYK). In the experiment, the in vivo GLYK was first characterized. Next, the thioredoxin (Trx) responsible for regulating the enzyme was identified and characterized as well. The findings were then compared to GLYK of dicotyledonous (Arabidopsis) and monocotyledonous (rice) C3 plants.

In assessing the in vivo activity of GLYK, GLYK activity was found to be low in the absence of 1, 4-dithio-DL-threitol (DTT), which cleaves disulfide bonds, but high in the presence of it. It needs light to function, as well. Next, 6 maize Trx genes were found from maize genome using sorghum Trx. The two type f Trx genes activated maize GLYK the most. Finally, in comparing maize GLYK to C3 plants, the Km of former was found to be similar to that of other plants in reducing conditions, but was only a third when DTT or Trx was absent.

In addition, maize GLYK is longer, having a C-terminal extension of seven amino acids, including 2 Cys residues that form a disulfide bond Overall, the research was able to identify the molecular mechanism of maize GLYK regulation, which is the disulfide bond at the C-terminal extension. However, the authors were mistaken when they said in the text that it is the Km, which is similar among the plants. They would have been more correct if they said it was Vmax, as table I suggests. In addition, it would have been better if the writers said that the values being compared are not significantly different from each other, because, in contrast to the text, they are not similar as well.