pyrofosforylase

Pyrofosforylase is an enzyme that catalyzes the conversion of pyrophosphoryl aspartate to phosphoribosylpyrophosphate (PRPP) and ammonia. This reaction is a key step in the synthesis of nucleotides from non- ribose sugar sources.

The enzyme is also known as phosphoribosyl PyroPhosphokinase-like (PRPK), due to its similarity in function and structure to the well-studied PRPK enzyme of E. coli. The human homolog of pyrofosforylase is encoded by the gene PRPS2, which is involved in the catabolic pathway for tryptophan.

Pyrofosforylase is primarily found in the liver, kidney, and brain tissues, and is involved in the breakdown of certain dietary amino acids. The enzyme exhibits a specificity for pyrophosphoryl aspartate as substrate, making it an essential component in the biochemical pathways involving nucleotide and amino acid metabolism.

The enzyme's activity has been implicated in the development of certain metabolic disorders, including Tay-Sachs and other lysosomal storage diseases. Deficiencies in pyrofosforylase have been linked to reduced levels of PRPP, which is essential for the synthesis of sialic acid, an important component of neuronal membranes.

Mutations in the PRPS2 gene have been associated with a range of neurological disorders, including spastic paraplegia, intellectual disability, and hearing loss. Research on the pyrofosforylase enzyme continues to unravel its molecular structure and biochemical mechanisms, shedding light on the complex relationships between nucleotide, amino acid, and porphyrin metabolism.