On the presence of a “particle-bound” neuraminidase in retina. A developmental study
1976; Elsevier BV; Volume: 18; Issue: 10 Linguagem: Inglês
10.1016/0024-3205(76)90138-7
ISSN1879-0631
AutoresH. Dreyfus, S. Harth, P.F. Urban, P. Mandel, Augusto Preti, A. Lombardo,
Tópico(s)Lysosomal Storage Disorders Research
ResumoNeuraminidase activity was detected in chicken retina. A “particle-bound” neuraminidase was demonstrated in retina; however no “soluble” neuraminidase was present. For the endogenous “particle-bound” neuraminidase the pH optimum was 4.0 and the enzyme was stimulated by 0.15 % Triton X-100. Total activity measured in the presence of both endogenous and GDla (0.085 mM) substrates, reached a maximum at the same pH (4.0) in the presence of lower amounts of Triton X-100 (0.075–0.1 %). An excess of GDla inhibited the activity. Total and endogenous activity profiles of the “particle-bound” neuraminidase behaved similarly during chick retina ontogenesis; the activities were low during the early embryo period, reached maximum levels near hatching and remained stable throughout adulthood. In chicken retina, neuraminidase, which may take part in ganglioside catabolism, reached the maximum of activity when the retina was morphologically mature, while glycosyltransferases, implicated in the first steps of retinal ganglioside synthesis, are known to attain maximum levels of activity at an early stage of brain development.
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