Alonso A C, Arce C A, Barra H S
Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina.
Biochim Biophys Acta. 1993 Apr 21;1163(1):26-30. doi: 10.1016/0167-4838(93)90274-u.
Using immunobinding and enzymatic assays we determined in rat muscle extracts the proportion of tyrosinatable tubulin, that is, tubulin that participates in the tyrosination/detyrosination cycle. We found that in muscle, in contrast with nervous tissue, practically all tubulin molecules are tyrosinatable. In the case of rat brain the non-tyrosinatable tubulin pool accounts for about 50% of the tubulin. In addition, isolectrofocusing of 14C-tyrosinated tubulin from brain and muscle extracts revealed a different composition in tyrosinatable tubulin isotypes. One of the isotypes, which in muscle accounts for 86% of the 14C-tyrosinated tubulin species, was detyrosinated by the action of tubulin carboxypeptidase faster than the rest of the 14C-tyrosinated tubulin isotypes taken in whole. In the case of brain extract, that isotype accounts for only 16% of the labeled tubulin.
