purine ribonucleoside monophosphate biosynthetic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the formation of purine ribonucleoside monophosphate, a compound consisting of a purine base linked to a ribose sugar esterified with phosphate on the sugar. [GOC:go_curators, ISBN:0198506732]

Purine ribonucleoside monophosphate biosynthesis, also known as de novo purine nucleotide biosynthesis, is a complex metabolic pathway that produces the purine nucleotides, adenine monophosphate (AMP) and guanine monophosphate (GMP), which are essential building blocks for DNA, RNA, and other vital biomolecules. This process occurs in the cytoplasm of cells and involves a series of enzymatic reactions that use simple precursor molecules, such as amino acids, carbon dioxide, and tetrahydrofolate, to build the purine ring structure.

The pathway can be broadly divided into two stages:

1. **Formation of the purine ring:** This initial stage involves a series of 10 enzymatic reactions that assemble the purine ring structure. It starts with the formation of phosphoribosyl pyrophosphate (PRPP) from ribose-5-phosphate, which acts as a precursor molecule for the purine ring. The subsequent steps involve the sequential addition of various precursor molecules, such as glycine, glutamine, aspartate, formate, and tetrahydrofolate, to the growing purine ring. The final product of this stage is inosine monophosphate (IMP), which is the first purine nucleotide formed.

2. **Conversion of IMP to AMP and GMP:** The second stage involves the conversion of IMP into AMP and GMP. IMP is converted to AMP by the enzyme adenylate kinase, which uses adenosine triphosphate (ATP) as a phosphate donor. GMP is synthesized from IMP through a two-step process. First, IMP is oxidized to xanthosine monophosphate (XMP) by IMP dehydrogenase. Then, XMP is converted to GMP by the enzyme GMP synthetase, which utilizes glutamine as a source of nitrogen.

The purine ribonucleoside monophosphate biosynthetic process is highly regulated to ensure that the appropriate levels of purine nucleotides are maintained in the cell. This regulation occurs at several levels, including the availability of precursor molecules, the activity of enzymes involved in the pathway, and the feedback inhibition by purine nucleotides.

In summary, purine ribonucleoside monophosphate biosynthesis is a fundamental metabolic pathway that plays a vital role in cell function. It provides the building blocks for DNA, RNA, and other essential molecules, and it is tightly regulated to ensure that the cell maintains the appropriate balance of purine nucleotides.'
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Proteins (5)

Compounds (34)