Formation of 5-Phosphoribosyl-1-Pyrophosphate

One-carbon transfer reactions involving folate-derived carriers. Dashed arrows indicate multiple-step reaction pathways solid arrows represent direct, single-step reactions. 

Methylation of deoxyuridylate to thymidylate (N, N °-methylene FH4) (an essential step in the biosynthesis of DNA impairment of this reaction is responsible for the main clinical manifestations of folate deficiency)  

Synthesis of formylmethionyl-tRNA (N -formyl FH4) required for initiation of protein synthesis in prokaryotes (Chapter 25) and in mitochondria and 

Inherited disorders of folate transport and metabolism include defects in folate carrier (hereditary folate malabsorption, previously discussed), deficiency of N, N °-methylene FH4 reductase (Chapter 17), or functional deficiency of N -methyl FH4 methyltransferase due to defects 

Several observational studies have shown that dietary supplementation of folate in women of childbearing age who might become pregnant can reduce the risk of fetal neural tube defects (e.g., spina bifida). 

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Attack at the /3 phosphate of ATP displaces AMP and transfers a pyrophosphoiyl (not pyrophosphate) group to the attacking nucleophile (Pig. 13-10b). For example, the formation of 5 -phosphoribosyl-1-pyrophosphate (p. XXX), a key intermediate in nucleotide synthesis, results from attack of an —OH of the ribose on the /3 phosphate. 

HERSHKO, A., HERSHKO, C. and MAOER, J. (1968). Increased formation of 5-phosphoribosyl-1-pyrophosphate in red blood cells of some gouty patients. Isr. J. Med. Sci. U 939 ... 

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