Phosphorylase yeast

Meyerhof s discovery in yeast extracts of a phosphorylase (which he named hexokinaseP) led to more detailed investigations of the specificity of this enzyme. The enzyme, which has been crystallized,89 converts D-glucose,... 

Scheme 9.5 Multi-step enzymatic process for 2 -deoxyribo-nucleoside production from glucose, acetaldehyde and a nucleobase through glycolysis, reverse reactions of 2 -deoxy-ribonucleoside degradation and ATP regeneration by the yeast glycolytic pathway recycling the phosphate generated by nucleoside phosphorylase.

It had been known from at least the time of Pasteur that the presence of sodium or potassium phosphate aided the progress of a yeast fermentation. Later intensive study showed that a complex group of enzymes (phosphatases and phosphorylases) was responsible for the phosphorylation, dephosphorylation and interconversion of D-glucose 6-phosphate, D-fructose 6-phosphate, D-fructose 1,6-diphosphate and similar substances in various types of cells and muscle tissue. Detailed reviews of the field are available. - A further advance was made in 1936, when Cori and Cori noted that in certain circumstances well-washed frog muscle immersed in a sodium phosphate buffer utilized the inorganic phosphate to produce a new hexose phosphate (the Cori ester). This compound was later shown to be a-D-glucopyranose-l-phosphate and yielded crystalline dipotassium and brucine salts. The Cori ester arose because... 

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 yeast enzyme is a homodimer of Mr2 X 102 500 and has 49% sequence identity to the muscle enzyme. The yeast enzyme is more simply regulated feedback inhibition by the allosteric inhibitor glucose-6-phosphate and activation by a 3 -5 -cyclic AMP-dependent protein kinase or a yeast phosphorylase that phosphorylates Thr-10.55... 

Kenny (1973) recommends a Soy peptone-yeast dialysate medium (Appendix 4) for culture of mycoplasma. Inclusion of arginine (16 mM) and 0.4 mg% phenol red indicates the presence of arginine deaminase by formation of alkali (purple coloration). Alternatively, incubation with tritiated thymidine and analysis of the culture medium for tritiated thymine can be used to detect thymidine phosphorylase (House and Waddell, 1967). 

Glu-170 of the catalytic subunit of cAMP-dependent protein kinase (protein kinase A), equivalent to Glu-153 of the 7-subunit of phosphorylase kinase, was labeled by l-ethyl-3-[3-diethylaminopropyl]carbodiimide.88) The modification of this residue was well protected by ATP and a peptide inhibitor together, but not by each one alone, consistent with the idea that the region around Glu-153 is the site for the binding of both substrates. Genetic study also confirmed the important role of the region around Glu-153. The mutation of Leu-217 of yeast protein kinase A, equivalent to Leu-155 of the 7-subunit of phosphorylase kinase, resulted in loss of protein kinase activity.891... 

The polyphosphate kinase from the yeast cell homogenate purified by Felter and Stahl (Felter and Stahl, 1973) was shown to be actually diadcnosinc-5,5,"-Pl, P4 tetraphosphate a,b-phosphorylase (AP4 phosphorylase). The enzyme acting in concert with one or more yeast polyphosphatases provided the production of 32P-labelled ATP in the presence of 32P-labelled PolyP and ADP (Booth and Guidoth, 1995) ... 

J. W. Booth and G. Guidotti (1995). An alleged yeast polyphosphate kinase is actually diadenosine-5, 5 "-P1,P4-tetraphosphate a,/3-phosphorylase. J. Biol. Chem., 270, 19377-19382. 

Phosphonomannans, fungal, 394,417 Phosphorus, in yeast mannan, 391 Phosphorylases active sites of, 346 amino acids of, 345 kinetics, 289,353 mechanism of action of, 356 properties of, 347... 

Endo- and exonucleases have been used successfully with nucleic acids and their analogs for organic synthetic purposes. For example, ATP was synthesized from AMP for use in cofactor recycling (Table 13-9, entry 1). The AMP was obtained from yeast RNA by cleavage with the nuclease Pi yielding a mixture of nucleoside monophosphates11011. In another report1731, nucleoside diphosphates were obtained by hydrolysis of RNA with nuclease Pi and a polynucleotide phosphorylase (the diphosphates are preferred because the diphosphates were more easily transformed to the nucleoside triphosphates than the monophosphates). 

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