A non-mitochondrial carboxylase, related to glutamate action is synthesized in the retina of the chick embryo.

SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot of chick retinal proteins at 21 days after intravitreal injection with 5 or 10 microM/eye Glu showed decreases in 37, 42, 53 and 57 kDa proteins and increases in 35, 72 and >94 kDa proteins. These proteins were carboxylases except for the 35 and 37 kDa proteins. With > or =15 microM/eye Glu, non-specific loss of retinal proteins was observed. In embryonic retinas, the 42 kDa protein was seen a few days before hatching, with biotin incorporation on days 3-6 after hatching. Immunohistochemistry indicated that this protein was a component of both the inner nuclear layer and the photoreceptor. Immunocytochemistry located it to the cell surface.