Problem 14 - Biochemistry

Question

What are three sources of deoxyuridylate in bacterial cells?

Step-by-Step Solution

Answer

Answer: The three sources of deoxyuridylate (dUMP) in bacterial cells are the reduction of ribonucleotide diphosphates (rNDPs), the deamination of deoxycytidine monophosphate (dCMP), and salvage pathways from free deoxyuridine (dU).

Step 1: Understanding deoxyuridylate (dUMP)

Deoxyuridylate, also known as deoxyuridine monophosphate (dUMP), is an intermediate in the biosynthesis of deoxythymidine monophosphate (dTMP), which is essential for DNA synthesis. It is derived from deoxyribonucleotides and plays a vital role in the proper functioning of bacterial cells.

Step 2: List the three sources of dUMP in bacterial cells

The three sources of deoxyuridylate (dUMP) in bacterial cells are: 1. Reduction of ribonucleotide diphosphates (rNDPs) 2. The deamination of deoxycytidine monophosphate (dCMP) 3. Salvage pathways from free deoxyuridine (dU)

Step 3: Explain the three sources of dUMP

1. Reduction of ribonucleotide diphosphates (rNDPs): Ribonucleotide reductase enzyme catalyzes the conversion of ribonucleotide diphosphates (like UDP) to deoxyribonucleotide diphosphates (like dUDP). dUDP is then converted to dUMP by nucleotide diphosphate kinase through the removal of a phosphate group. 2. The deamination of deoxycytidine monophosphate (dCMP): Deoxycytidine monophosphate (dCMP) is converted to deoxyuridylate (dUMP) by the action of the enzyme dCMP deaminase. This reaction involves the removal of an amino group from dCMP, which is replaced by an oxygen atom, forming dUMP. 3. Salvage pathways from free deoxyuridine (dU): In this pathway, free deoxyuridine (dU) is salvaged and converted to deoxyuridylate (dUMP) through the action of thymidine kinase. The enzyme adds a phosphate group to deoxyuridine, creating dUMP.