Tyrosine hydroxylase (TH) is the rate-limiting enzyme in the formation of dopamine. It catalyses the hydroxylation of L-tyrosine to form L-DOPA, an intermediate of catecholamine biosynthesis. [1] The catecholamines dopamine, adrenalin and noradrenalin play important roles in the human organism as neurotransmitters and hormones. [2]
Tyrosine hydroxylase consists of three domains: N-terminal regulatory domain, catalytic domain and C-terminal tetramerization domain. Activity of TH rapidly increases after phosphorylation of S19 and S40 situated within the regulatory domain and its subsequent interaction with 14-3-3 proteins. [3] Recently, the regulatory domain of TH was described as a stable dimer at physiological conditions. [4]
In order to describe dimer-monomer equilibria of regulatory domain of human TH, we designed an assay based on the self-quenching phenomenon for determination of dissociation rate constant. The temperature dependency of the dissociation rate constant allowed us to obtain an estimated value for the energy barrier of dissociation of the regulatory domain.
This
work was supported by the Ministry of Education, Youth and Sports
within the program INTER-ACTION (LTAUSA18168). The results of this research have been acquired within the CEITEC
2020 (LQ1601) project with financial contribution made by the Ministry of
Education, Youths and Sports of the Czech Republic within special support paid
from the National Programme for Sustainability II funds.