A homozygous deletion in RPE65 in a small Sardinian family with autosomal recessive retinal dystrophy.

Purpose: We have been engaged in an ongoing study to screen candidate genes for mutations in small families with various forms of autosomal recessive retinal dystrophy. Here we report the screening of a cohort of 14 families from Sardinia for mutations in the genes encoding the alpha- and beta-subunits of cGMP-phosphodiesterase and RPE65 (PDE6A, PDE6B, and RPE65).

Methods: Haplotype analysis was performed on each family using simple sequence repeat markers closely flanking or within each of the three gene candidates.

Metabolite activation of crassulacean Acid metabolism and c(4) phosphoenolpyruvate carboxylase.

The effects of glycine, alanine, serine, and various phosphorylated metabolites on the activity of phosphoenolpyruvate (PEP) carboxylase from Zea mays and Crassula argentea were studied. The maize enzyme was found to be activated by amino acids at a site that is separate from the glucose 6-phosphate binding site. The combination of glycine and glucose 6-phosphate synergistically reduced the apparent K(m) of the enzyme for PEP and increased the apparent V(max).