Interestingly, the only N-acetylati

Interestingly, the only N-acetylation among Acb proteins was identified in the putative acarbose 4-alphaglucanotransferase AcbQ during the middle of the growth phase (T3; 72.3 h). Since N-terminal acetylation can affect the protein stability in both directions [60– 64], it can be assumed that stability of AcbQ is posttranslational influenced. Interestingly, AcbQ shows one of the most stable protein abundances among Acb proteins over the cultivation process (Fig. 8). This could indicate, that AcbQ possibly plays an important role in the physiology of Actinoplanes sp. SE50/110, e.g. within the acarbose metabolism. However, the specific function of AcbQ in the acarbose biosynthesis pathway has not yetbeen proven [13, 18]. Nevertheless, if AcbQ is an important enzyme in Actinoplanes sp. SE50/110 preventing its degradation is a possible action to increase production by the cell [65, 66]. It is notably, that most of the glutamine to pyroglutamic acid modifications of the Acb proteins were identified during the filamentous growth phase (72.3 h and 96.5 h). This could be a hint for altered enzymatic activity during filamentous growth caused by this modification. Nevertheless, this has to be proven by further experiments.