4-Aminobutyraldehyde and 4-Guanidinobutyraldehyde Dehydrogenases for Arginine Degradation inPseudomonas putida

l-Arginine induced two NAD+-specific dehydrogenases acting on 4-guanidinobutyraldehyde (GBAL) in Pseudomonas putida ATCC 12633. One was identified as 4-aminobutyraldehyde dehydrogenase because it was induced by putrescine also and was active toward 4-aminobutyraldehyde (ABAL). The other was specific for GBAL and was identified as GBAL dehydrogenase. We purified both enzymes. The molecular weight and the subunit weight of ABAL dehydrogenase were 240,000 and 57,000, respectively. GBAL dehydrogenase had a molecular weight of 107,000 and a subunit weight of 57,000. ABAL dehydrogenase was most active toward ABAL at pH 8.0 and toward GBAL at pH 8.5 to 9.5. This enzyme dehydrogenated ABAL (100%), GBAL (130%), 5-aminovaleraldehyde (100%), valeraldehyde (66%), butyraldehyde (66%), and propionaldehyde (49%). The apparent Km values for ABAL and NAD+ were estimated to be 0.26 and 0.05 mm, respectively. GBAL dehydrogenase exhibited the optimum pH to be 9.0 and the high substrate specificity for GBAL. The apparent Km values for GBAL and NAD+ were 0.03 and 0.14mM, respectively. This enzyme was readily inactivated in the absence of 2-mercaptoethanol, and NAD+ and 2-mercaptoethanol were required for full reactivation of the inactivated enzyme.