Tryptophan synthase beta chain TRPB_NEIGO trpB 400 MKNYHAPDEKGFFGEHGGLYVSETLIPALKELEQAYNEAKNDPEFWAEFRRDLKHYVGRPSPVYHAARLSEHLGGAQIWLKREDLNHTGAHKVNNTIGQALLARRMGKKRVIAETGAGQHGVASATVAARFGMTSDVYMGADDIQRQMPNVFRMKLLGANVIGVDSGSRTLKDAMNEAMREWVARVDDTFYIIGTAAGPAPYPEMVRDFQCVIGNEAKAQMQEATGRQPDVAVACVGGGSNAIGLFYPYIEEENVRLVGVEAGGLDVDTPDHAAPITSGAPIGVLHGFRSYLMQDENGQVLGTHSVSAGLDYPGIGPEHSHLHDIKRVEYTVAKDDEALEAFDLLCRFEGIIPALESSHVVGSGDKTRRKMGKDQVILVNLSGRGDKDINTVAKLKGIEL The beta subunit is responsible for the synthesis of L- tryptophan from indole and L-serine.