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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Which among the following are the substrates needed for purine salvage pathway?
assistant
The correct answer is  Conversion of purines, their ribonucleosides, and their deoxyribonucleosides to mononucleotides involves "salvage reactions". The more impoant mechanism involves phosphoribosylation by PRPP of a free purine (Pu) to form a purine 5'-mononucleotide (Pu-RP). Phosphoryl transfer from ATP, catalyzed by adenosine- and hypoxanthine-phosphoribosyl transferases, conves adenine, hypoxanthine, and guanine to their mononucleotides. A second salvage mechanism involves phosphoryl transfer from ATP to a purine ribonucleoside. Phosphorylation of the purine nucleotides, catalyzed by adenosine kinase, conves adenosine and deoxyadenosine to AMP and dAMP. Similarly, deoxycytidine kinase phosphorylates deoxycytidine and 2'-deoxyguanosine, forming dCMP and dGMP. Ref: Rodwell V.W. (2011). Chapter 33. Metabolism of Purine & Pyrimidine Nucleotides. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.