The influence of selected O-alkyl derivatives of cyclodextrins on the enzymatic decomposition of L-tryptophan by L-tryptophan indole-lyase.
A series of O-alkyl derivatives of cyclodextrin: heksakis[2,3,6-tri-O-(2'-methoxyethyl)]-alpha-cyclodextrin; heksakis(2,3-di-O-methyl)-alpha-cyclodextrin; heptakis(2,3-di-O-methyl)-beta-cyclodextrin; heksakis[2,3-di-O-methyl-6-O-(2'-methoxyethyl)]-alpha-cyclodextrin; heptakis[2,3-di-O-methyl-6-O-(2'-methoxyethyl)]-beta-cyclodextrin; heksakis[2,3-di-O-(2'-methoxyethyl)]-alpha-cyclodextrin and heptakis[2,3-di-O-(2'-methoxyethyl)]-beta-cyclodextrin have been synthesized. Purity and composition of the obtained substances were examined. The cyclodextrin derivatives listed above as well as (2-hydroxypropyl)-alpha-cyclodextrin and (2-hydroxypropyl)-beta-cyclodextrin, the two commercially available ones, have been investigated as the additives in the course of enzymatic decomposition of L-tryptophan by L-tryptophan indole-lyase. It has been found that each of cyclodextrin derivatives causes the inhibition of enzymatic process, both competitive and non-competitive. The competitive inhibition is connected with the formation of inclusion complexes between cyclodextrins and L-tryptophan, related to the geometry of these complexes. The mechanism of the non-competitive inhibition is not so evident; it could be related to the formation of the cyclodextrin complexes on the surface of the enzyme, leading to the change in the flexibility of the enzyme molecule.
Gubica
Tomasz
T
Department of Chemistry, University of Warsaw, Pasteura 1, PL-02093 Warsaw, Poland.
Winnicka
Elzbieta
E
Temeriusz
Andrzej
A
Kańska
Marianna
M
D001667:Binding, Competitive; D002384:Catalysis; D003505:Cyclodextrins / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry*; D014364:Tryptophan / Q000737:chemistry / Q000187:drug effects*; D014368:Tryptophanase / Q000737:chemistry* / Q000494:pharmacology
D003505:Cyclodextrins; D014364:Tryptophan; D014368:Tryptophanase; D010100:Oxygen