Regulation mechanism repression

The molecular mechanism underlying the inhibition remains unclear. It could comprise the simple product inhibition due to binding of PS to either catalytic site or the regulatory site of PSS I. It is also possible that a putative regulator molecule may bind PSS I to repress the PSS I activity in the presence of excess PS and that Arg-95 of PSS I may be essential for this binding. Determination of the three-dimensional structure of PSS I may provide a new insight into the role of Arg-95 of PSS I in the feedback regulation mechanism. 

The variety of translational regulation mechanisms provides flexibility, allowing focused repression of a few mRNAs or global regulation of all cellular translation. 

The screening method based on diameter of halos yielded only five strains with at least 20% more PG than wild t> e. Most attempts to enhance pectinase production have been made in filamentous fiingi, in which enzyme production is regulated by induction and catabolite repression mechanisms [8], By contrast, PG produced by marxianus is constitutive and not subject to catabolite repression [6], Failure to find greatly enhanced secretion levels is consistent with the idea of a constitutive gene that is capable of only modest further induction. PG was found in this study to be already the most prolific secreted protein of K. marxianus. 

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