Transferases;
Transferring alkyl or aryl groups, other than methyl groups;
Transferring alkyl or aryl groups, other than methyl groups (only sub-subclass identified to date)

putrescine:putrescine 4-aminobutyltransferase (ammonia-forming)

(1) 2 putrescine = sym-homospermidine + NH3 + H+ [RN:R00018];
(2) putrescine + spermidine = sym-homospermidine + propane-1,3-diamine [RN:R01919]

R00018 R01919

putrescine [CPD:C00134];
spermidine [CPD:C00315]

The reaction of this enzyme occurs in three steps, with some of the intermediates presumably remaining enzyme-bound: NAD+-dependent dehydrogenation of putrescine, transfer of the 4-aminobutylidene group from dehydroputrescine to a second molecule of putrescine and reduction of the imine intermediate to form homospermidine. Hence the overall reaction is transfer of a 4-aminobutyl group. Differs from EC 2.5.1.45, homospermidine synthase (spermidine-specific), which cannot use putrescine as donor of the aminobutyl group.

EC 2.5.1.44 created 1999, modified 2001

1  [PMID:437275]

Tait GH.

The formation of homospermidine by an enzyme from Rhodopseudomonas viridis [proceedings]

Biochem Soc Trans 7:199-201 (1979)

2

Bottcher, F., Ober, D. and Hartmann, T.

Biosynthesis of pyrrolizidine alkaloids: putrescine and spermidine are essential substrates of enzymatic homospermidine formation.

Can J Chem 72:80-85 (1994)

3  [PMID:8407874]

Yamamoto S, Nagata S, Kusaba K.

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

J Biochem (Tokyo) 114:45-9 (1993)

4  [PMID:7470060]

Srivenugopal KS, Adiga PR.

Enzymic synthesis of sym-homospermidine in Lathyrus sativus (grass pea) seedlings.

Biochem J 190:461-4 (1980)

5

Ober, D., Tholl, D., Martin, W. and Hartmann, T.

Homospermidine synthase of Rhodopseudomonas viridis: Substrate specificity and effects of the heterologously expressed enzyme on polyamine metabolism of Escherichia coli.

J Gen Appl Microbiol 42:411-419 (1996)

6  [PMID:10611289]

Ober D, Hartmann T.

Homospermidine synthase, the first pathway-specific enzyme of pyrrolizidine alkaloid biosynthesis, evolved from deoxyhypusine synthase.

Proc Natl Acad Sci U S A 96:14777-82 (1999)
DOI:10.1073/pnas.96.26.14777