[HPr protein]-L-serine + diphosphate => [HPr protein]-O-phospho-L-serine + phosphate + H(+)
[hpr protein]-l-serine + diphosphate => [hpr protein]-o-phospho-l-serine + phosphate + h(+)
[HPr protein]-L-serine + diphosphate => [HPr protein]-O-phospho-L-serine + phosphate + H(+)
[hpr protein]-l-serine + diphosphate => [hpr protein]-o-phospho-l-serine + phosphate + h(+)