Biosynthesis of human α-N-acetylgalactosaminidase: Defective phosphorylation and maturation in infantile α-NAGA deficiency

The biosynthesis of human α-N-acetylgalactosaminidase (α-NAGA) was studied in normal fibroblasts and in cells from patients with infantile α-NAGA deficiency. Normal α-NAGA is synthesized as a 52 kDa precursor which matures to a 49 kDa species through phosphorylation and carbohydrate trimming. Fibroblasts from the patients synthesize normal amounts of a 52 kDa precursor, however phosphorylation does not occur and this precursor is subsequently degraded intracellularly.