Enzymatic Production of High Concentration Glucose-1-Phosphate
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Glucose-1-phosphate (G-1-P) is a biological product which, along with its derivatives, has various physiological applications. In order to develop an efficient industrial process for G-1-P, enzymatic production of high concentration G-1-P was attempted by using phosphorylase purified from potatoes as an enzyme, several kinds of linear and branched dextrin differing in chain length and a mixture of KH<SUB>2</SUB>PO<SUB>4</SUB> and K<SUB>2</SUB>HPO<SUB>4</SUB> (Pi) as substrates. Since the maltotetraose is not active as a substrate for production of G-1-P, effective glucan concentration was defined on a basis of moles of glucose (<I>C</I><SUB>eG</SUB>) excluding a segment of maltotetraose from dextrin. Furthermore, since the reaction was a complicated reversible reaction involving many kinds of glucan differing in chain length, the inhibitory effect of a high concentration of substrate for the enzyme, an apparent equilibrium constant <I>K</I><SUB>app</SUB> was defined. <I>K</I><SUB>app</SUB> was expressed as a function of initial concentration of glucan (<I>C</I><SUB>eG,0</SUB>) and phosphate (<I>C</I><SUB>P,0</SUB>). The concentration of G-1-P finally obtained at the equilibrium (<I>C</I><SUB>G1P,eq</SUB>) could be easily calculated from <I>K</I><SUB>app</SUB> regardless of chain length and branch structures of glucan. As a result, a diagram expressing <I>C</I><SUB>G1P,eq</SUB> as a function of <I>C</I><SUB>eG,0</SUB> and <I>C</I><SUB>P,0</SUB> was proposed. A high concentration of G-1-P, namely 230 mM G-1-P was experimentally obtained when <I>C</I><SUB>eG,0</SUB> and <I>C</I><SUB>P,0</SUB> were 516 and 3000 mM, respectively, and the enzymatic activity was 100 U·mL<SUP>–1</SUP>.
- JOURNAL OF CHEMICAL ENGINEERING OF JAPAN
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 41(4), 306-311, 2008-04-01
The Society of Chemical Engineers, Japan