FIG 4 .

Significantly enriched proteins in purine de novo biosynthesis and salvage pathways in L. delbrueckii subsp. bulgaricus LBB.B5-R during milk incubation at 37°C. The symbol * indicates increased but not significant protein changes. The following abbreviations are used: ribose-5-P, ribose-5-phosphate; PRPP, phosphoribosyl pyrophosphate; PRA, phosphoribosyl amine; GAR, glycinamide ribonucleotide; (formyl-)THF, (formyl-)tetrahydrofolate; FGAR, formylglycinamide ribonucleotide; FGAM, formylglycinamidine ribonucleotide; AIR, aminoimidazole ribonucleotide; CAIR, phosphoribosyl carboxyaminoimidazole; SAICAIR, succinocarboxamide carboxyaminoimidazole ribonucleotide; AICAR, aminoimidazole carboxamide ribonucleotide; FAICAR, formaminoimidazole carboxamide ribonucleotide; sAMP, adenylsuccinate; A, adenine; G, guanine. Full names of the enzymes are listed as follows: Prs, PRPP synthase; PurF, PRPP amidotransferase; PurN, GAR transformylase; Fhs, formate-tetrahydrofolate ligase; PurQS, FGAM synthase; PurM, AIR synthase; PurEK, CAIR synthase; PurC, SAICAR synthase; PurB, adenylosuccinate lyase; PurH, bifunctional AICAR transformylase/IMP cyclohydrolase; PurA, adenylosuccinate synthase; Apt, adenine phosphoribosyltransferase; GuaB, IMP dehydrogenase; GuaA, GMP synthase; Hpt, hypoxanthine-guanine phosphoribosyltransferase; IunH, nucleoside (inosine/uridine) hydrolase.