Please I need help answering these questions. Thanks. 1. Purine nucleotide metab
ID: 253690 • Letter: P
Question
Please I need help answering these questions. Thanks.
1. Purine nucleotide metabolism is controlled at two critical points, Gin:PRPP amidotransferase, and thase. The first the branch point for IMP metabolism, IMP dehydrogenase and adenylosuccinate syn enzyme is controlled by all the purine nucleotide mono, di, and triphosphates, whereas the IMP branch is only controlled by the monophosphates. What is the advantage to the cell of this control pattern? 2. Provide a reasonable chemical mechanism for the conversion of IMP to adenylosuccinate (this is arn oxo/amine exchange The accuracy rate for DNA polymerase falls if the next nucleotide to be polymerized is present in high concentration. Conversely, the accuracy rate rises if the next nucleotide is present in low concentration. These phenomena are termed the "next nucleotide effect." Suggest an explanation for this effect. 3.Explanation / Answer
1.) The enzymes involved in nucleotide metabolism are regulated at the enzyme level by allosteric interaction, mainly by feedback inhibition.
As given in question, purine biosynthesis is controlled by AMP and GMP and Pi that act on PRPP synthase and by adenosine and guanosine mono, di or triphosphates at two sites.
The enzyme activity therefore depend not only on the concentration of the immediate substrate, but also on the end products. Substrate availibility of the cells can be an important means of controlling flux.
The cell has the advantage as this control pattern is useful in controlling energy of the cell.