Human brain glycogen phosphorylase: characterization of fetal cDNA and genomic sequences

Glycogen phosphorylase (alpha-1,4-glucan:orthophosphate D-glucosyltransferase, EC 2.4.1.1) is the rate-determining enzyme catalyzing glycogen degradation. Human brain has been demonstrated previously to express genes of both the liver and muscle isozymes of glycogen phosphorylase. In this report, a human fetal brain cDNA and genomic DNA corresponding to the brain isozyme of glycogen phosphorylase were isolated and characterized. Transcripts corresponding to this isozyme are present in human adult and fetal brain, and at low levels in other human fetal tissues. The predicted C-terminal sequence of the protein encoded by this cDNA and gene differ from that encoded by a phosphorylase cDNA isolated from a human astrocytoma cell line.