Send to

Choose Destination
See comment in PubMed Commons below
J Biochem. 1993 Jul;114(1):45-9.

Purification and characterization of homospermidine synthase in Acinetobacter tartarogenes ATCC 31105.

Author information

  • 1Faculty of Pharmaceutical Sciences, Okayama University.


Homospermidine synthase, catalyzing the formation of homospermidine [H2N(CH2)4NH-(CH2)4NH2] from putrescine and NAD+ with concomitant liberation of NH3, was purified 600-fold over the crude extract with a yield of about 14% to homogeneity from Acinetobacter tartarogenes ATCC 31105. The enzyme had a native molecular mass of 102 kDa, with a pI of 5.0, and was apparently composed of two identical subunits (52 kDa), suggesting that a single protein catalyzes two serial reactions, oxidation of putrescine to 4-aminobutyraldehyde and subsequent reduction of the putative Schiff base formed between this aldehyde and a second molecule of putrescine to homospermidine. The Km values for putrescine and NAD+ were 280 and 18 microM, respectively. 1,3-Diaminopropane and cadaverine were inactive as substrates, and NAD+ could not be replaced by NADP+. 1,3-Diaminopropane and NADH were potent competitive inhibitors. The enzyme had a pH optimum of 8.7, was most active at 30 degrees C, and required K+ and dithiothreitol for full activity. Putrescine and NAD+ protected the enzyme from the inhibition by thiol reagents. The NH2-terminal amino acid sequence was AQWPVYGKISGPVVI. Some of these properties were compared with those of the homospermidine synthases from a photosynthetic bacterium, Rhodopseudomonas viridis and a plant, Lathyrus sativus.

[PubMed - indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for J-STAGE, Japan Science and Technology Information Aggregator, Electronic
    Loading ...
    Write to the Help Desk