Radioactive TLC analysis of the conversion of rac-pSer(P) to l-[14C(U)]-Leu-Ala(P) by DhpH and DhpD in a one-pot reaction. (A) Reaction scheme. (B) Reaction progress and scanned phosphorimaging plate of silica TLC sheets spotted with: lane 1, aliquot of a reaction containing DhpH, rac-pSer(P), l-[14C(U)]-Leu, tRNA and (re)generation components of Leu-tRNALeu; lane 2, aliquot of a reaction containing l-Ala in addition to the components in lane 1; lane 3, aliquot of a reaction containing l-Ala and DhpD in addition to the components in lane 1.