9.0) optimal pH, more than two pH units higher than that of vertebrate AANATs. Conclusions The substrate selectivity profiles of bfAANATα and δ' are relatively broad, including alkylamines, arylalkylamines and diamines, in contrast to vertebrate forms, which selectively acetylate serotonin and other arylalkylamines. Based on these features, it appears that amphioxus AANATs could play several roles, including detoxification and biogenic amine inactivation. The presence of seven AANATs in amphioxus genome supports the view that arylalkylamine and polyamine acetylation is important to the biology of this organism and that these genes evolved in response to specific pressures related to requirements for amine acetylation."/>
Skip to main content

Table 1 Kinetic characteristics of GST-bfAANAT and GST-bfAANAT ' for selected amines.

From: Evolution of AANAT: expansion of the gene family in the cephalochordate amphioxus

  Substrate
  Phenylethylamine Tyramine Serotonin Tryptamine
bfAANAT α δ' α δ' α δ' α δ'
V max 17.8 ± 1.1 4.9 ± 3 2.06 ± 0.28 0.78 ± .06 1.60 ± 0.1 0.56 ± 0.06 4.7 ± 0.8 2.7 ± 0.25
K m 3 ± 0.6 45 ± 36 8.2 ± 2.70 0.80 ± 0.28 0.01 ± 0.01 <0.01 8.1 ± 3.6 2.5 ± 0.7
  Substrate
  Octopamine Propylamine Butylamine Putrescine
bfAANAT α δ' α δ' α δ' α δ'
V max 2.1 ± 0.2 0.80 ± 0.05 >10 0.73 ± 0.07 32.5 ± 4.1 0.7 ± 0.05 1.34 ± 0.32 5.11 ± 0.11
K m 6.8 ± 1.9 0.05 ± 0.01 >20 0.90 ± 0.37 47.5 ± 8.0 0.37 ± 0.23 5.2 ± 4.0 3.68 ± 0.22
  1. Activity was measured at pH 9.0. Values are calculated from data in Figure 7. V max values are nmol/h/pmol enzyme and are given as the mean ± S.E.M. (N = 3 to 6). For further details see Methods.