Phosphorylase phosphatase: Molecular configuration and activity

Phosphorylase phosphatase activity in Saccharomyces cerevisiae 257.

A phosphatase, active towards phosphorylase a and phosphorylated proteins casein and histone II-A, was isolated from Saccharomyces cerevisiae 257. The enzyme dephosphorylated glycogen phosphorylase from commercial yeast rendering it inactive. The protein phosphatase activity was not influenced by any metal ions. Phosphorylase phosphatase activity was slightly stimulated by p-nitrophenyl phospha...

Mammalian phosphorylase phosphatase.

Phosphorylase phosphatase converts phosphorylase a into phosphorylase b. It was the first interconverting enzyme to be discovered (Cori & Green, 1943) and is the best characterized of the protein phosphatases involved in the regulation of glycogen metabolism, although its enzymology is still incompletely understood (for a review see Lee et al., 1976). We have developed a procedure for the isola...

Specificity studies on muscle phosphorylase phosphatase.

Molecular cloning of a cDNA for the catalytic subunit of rabbit muscle phosphorylase phosphatase.

A cDNA coding for the catalytic subunit of phosphorylase phosphatase (phosphatase C-I/phosphatase-1c) was cloned from a rabbit muscle cDNA library by screening with oligonucleotide probes. Ten clones were analyzed. The full cDNA sequence of 1395 base pairs contained an open reading frame of 990 base pairs flanked by 3' and 5' noncoding regions of 84 and 321 base pairs, respectively. The DNA seq...

Deficiency in phosphorylase phosphatase activity despite elevated protein phosphatase type-1 catalytic subunit in skeletal muscle from insulin-resistant subjects.

Glycogen synthase is activated by protein phosphatase type-1 (PP-1). The spontaneous PP-1 activity accounts for only a small fraction of total PP-1 activity, which can be exposed by trypsin digestion of inhibitor proteins in the presence of Mn2+. We determined total PP-1 activity in muscle biopsies from insulin-sensitive and -resistant nondiabetic Pima Indians. Inhibitor-2 sensitive PP-1 repres...