Yeast glycogen phosphorylase

The fact that glycogen phosphorylase can be used to polymerize amylose was first demonstrated by Schaffner and Specht [110] in 1938 using yeast phosphorylase. Shortly after, the same behavior was also observed for other phosphorylases from yeast by Kiessling [111, 112], muscles by Cori et al. [113], pea seeds [114] and potatoes by Hanes [115], and preparations from liver by Ostern and Holmes [116], Cori et al. [117] and Ostern et al. [118]. These results opened up the field of enzymatic polymerizations of amylose using glucose-1-phosphate as monomer, and can be considered the first experiments ever to synthesize biological macromolecules in vitro. 

The free energy change in phosphorolysis compared to hydrolysis is much closer to zero, and thus the known phosphorolytic enzymes catalyze biosynthetic reactions as well as catabolic changes. They are implicated chiefly in the synthesis of starch by plants and glycogen by animals. Recent work by Kornberg and his associates has pointed to a pyro-phosphorylase in yeast and hog liver that catalyzes the following general reaction ... 

---