Metabolic changes in a pyruvate kinase gene deletion mutant of Corynebacterium glutamicum ATCC 13032.
To investigate primary effects of a pyruvate kinase (PYK) defect on glucose metabolism in Corynebacterium glutamicum, a pyk-deleted mutant was derived from wild-type C. glutamicum ATCC13032 using the double-crossover chromosome replacement technique. The mutant was then evaluated under glutamic acid-producing conditions induced by biotin limitation. The mutant showed an increased specific rate of glucose consumption, decreased growth, higher glutamic acid production, and aspartic acid formation during the glutamic acid production phase. A significant increase in phosphoenolpyruvate (PEP) carboxylase activity and a significant decrease in PEP carboxykinase activity occurred in the mutant, which suggested an enhanced overall flux of the anaplerotic pathway from PEP to oxaloacetic acid in the mutant. The enhanced anaplerotic flux may explain both the increased rate of glucose consumption and the higher productivity of glutamic acid in the mutant. Since the pyk-complemented strain had similar metabolic profiles to the wild-type strain, the observed changes represented intrinsic effects of pyk deletion on the physiology of C. glutamicum.
Laboratory of Microbial Physiology, Research Faculty of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
Kazunori
K
Sawada
Susumu
S
Zen-in
Masaru
M
Wada
Atsushi
A
Yokota
D001224:Aspartic Acid / Q000096:biosynthesis; D001710:Biotin / Q000378:metabolism; D048230:Corynebacterium glutamicum / Q000201:enzymology* / Q000235:genetics*; D005947:Glucose / Q000378:metabolism; D018698:Glutamic Acid / Q000096:biosynthesis; D053858:Metabolic Networks and Pathways; D062907:Oxaloacetic Acid / Q000032:analysis; D019764:Phosphoenolpyruvate Carboxykinase (ATP) / Q000032:analysis; D010730:Phosphoenolpyruvate Carboxylase / Q000032:analysis; D011770:Pyruvate Kinase / Q000235:genetics* / Q000378:metabolism*; D017384:Sequence Deletion
D062907:Oxaloacetic Acid; D001224:Aspartic Acid; D018698:Glutamic Acid; D001710:Biotin; D011770:Pyruvate Kinase; D010730:Phosphoenolpyruvate Carboxylase; D019764:Phosphoenolpyruvate Carboxykinase (ATP); D005947:Glucose