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An experimental study on carbon flow in Escherichia coli as a function of kinetic properties and expression levels of the enzyme phosphoglucomutase
Author(s) -
Brautaset Trygve,
Petersen Steffen,
Valla Svein
Publication year - 1998
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/(sici)1097-0290(19980420)58:2/3<299::aid-bit27>3.0.co;2-6
Subject(s) - phosphoglucomutase , amylose , maltose , substrate (aquarium) , biochemistry , chemistry , enzyme , escherichia coli , mutant , galactose , biology , starch , ecology , gene
Mutants of Escherichia coli deficient in phosphoglucomutase accumulate amylose when the cells are grown on maltose or galactose as carbon source. In the presence of physiological levels of phosphoglucomutase, most of the sugar is catabolized, leading to strongly reduced levels of amylose accumulation. By varying the expression level of heterologous phosphoglucomutase, we show that the minimum level needed to block amylose accumulation corresponds to a phosphoglucomutase activity of 150–600 nmole substrate transformed per min per mg of total soluble protein. Mutant phosphoglucomutases with strongly reduced V max values and increased Km values for the substrate glucose‐1‐phosphate or the co‐substrate glucose‐1,6‐diphosphate, could also reduce amylose accumulation, but much higher enzyme expression levels were required. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 58:299–302, 1998.