Polyamine N-acetyltransferase in Leishmania amazonensis.
N-Acetyltransferase, which is suggested to be responsible for the production of N1-acetylspermidine in Leishmania amazonensis and to be involved in the process of inactivation and degradation of excessive polyamines, was partially purified and characterized. Among the substrates tested, sym-norspermidine, sym-norspermine, and 1,3-diaminopropane had the highest reaction rates, but the naturally occurring polyamines spermine and spermidine were also acetylated at considerable rates, whereas putrescine was a poor substrate. The Michaelis constants (Km values) for spermine and spermidine were 0.66 and 3.3 mM, respectively. The Km value for acetylcoenzyme A (acetyl-CoA) was determined to be 34 microM. CoA inhibited the reaction in a competitive manner; the inhibition constant was 5 microM. The enzyme showed an apparent relative molecular mass of 35,000.
Rojas-Chaves
M
M
Department of Biochemical Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
Hellmund
C
C
Walter
R D
RD
D000123:Acetyltransferases / Q000032:analysis*; D000818:Animals; D007894:Leishmania mexicana / Q000201:enzymology*; D013379:Substrate Specificity
D000123:Acetyltransferases; C030992:polyamine N-acetyltransferase