2.5.1.22 D201A 40000fold decrease in ratio kcat/Km value 687717 2.5.1.22 D201A mutation of Asp201 to Ala decreases the kcat/Km for decarboxylated S-adenosylmethionine by more than 100000fold 692270 2.5.1.22 D201N 40000fold decrease in ratio kcat/Km value 687717 2.5.1.22 D201N mutation of Asp201 to Asn decreases the kcat/Km for decarboxylated S-adenosylmethionine by more than 100000fold 692270 2.5.1.22 D276N 250000fold decrease in ratio kcat/Km value 687717 2.5.1.22 D276N alteration of this residue reduces the kcat/Km for spermidine by more than 200000fold 692270 2.5.1.22 DELTA1-129 0.02% activity compared to the wild-type enzyme 692270 2.5.1.22 DELTA1-145 no activity 692270 2.5.1.22 DELTA1-19 0.003% activity compared to the wild-type enzyme 692270 2.5.1.22 DELTA1-43 0.0002% activity compared to the wild-type enzyme 692270