XMP + diphosphate = xanthine + 5-phospho-alpha-D-ribose 1-diphosphate
xmp + diphosphate = xanthine + 5-phospho-alpha-d-ribose 1-diphosphate
XMP + diphosphate = xanthine + 5-phospho-alpha-D-ribose 1-diphosphate
xmp + diphosphate = xanthine + 5-phospho-alpha-d-ribose 1-diphosphate