Reaction of alpha-tubulin with iodotyrosines catalyzed by tubulin:tyrosine ligase: carboxy-terminal labeling of tubulin with [125I]monoiodotyrosine.
We have studied the capacity of different iodinated derivatives of phenylalanine and tyrosine to inhibit the incorporation of [3H]tyrosine into tubulin catalyzed by tubulin:tyrosine ligase. In contrast to thyronine and its iodinated derivatives, iodotyrosines were efficient inhibitors. That they also functioned as substrates of the enzyme was shown by the effective incorporation of [125I]mono- and diiodotyrosine into tubulin. The label was shown to be located at the carboxy terminus. Labeling by this method conserves the polymerization capacity of tubulin in contrast with classical radioiodination methods involving oxidation.
Joniau
M
M
Interdisciplinary Research Center, K.U. Leuven Campus Kortrijk, Belgium.
Coudijzer
K
K
De Cuyper
M
M
D007457:Iodine Radioisotopes / Q000378:metabolism; D007553:Isotope Labeling / Q000379:methods*; D007470:Monoiodotyrosine / Q000378:metabolism* / Q000494:pharmacology; D010453:Peptide Synthases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D015202:Protein Engineering; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D013970:Thyronines / Q000378:metabolism / Q000494:pharmacology; D014404:Tubulin / Q000378:metabolism*; D014443:Tyrosine / Q000494:pharmacology
D007457:Iodine Radioisotopes; D013970:Thyronines; D014404:Tubulin; D014443:Tyrosine; D010649:Phenylalanine; D010453:Peptide Synthases; C023213:tyrosyltubulin ligase; D007470:Monoiodotyrosine