Enzymes of glucose and methanol metabolism in the actinomycete Amycolatopsis methanolica.
The actinomycete Amycolatopsis methanolica was found to employ the normal bacterial set of glycolytic and pentose phosphate pathway enzymes, except for the presence of a PPi-dependent phosphofructokinase (PPi-PFK) and a 3-phosphoglycerate mutase that is stimulated by 2,3-bisphosphoglycerate. Screening of a number of actinomycetes revealed PPi-PFK activity only in members of the family Pseudonocardiaceae. The A. methanolica PPi-PFK and 3-phosphoglycerate mutase enzymes were purified to homogeneity. PPi-PFK appeared to be insensitive to the typical effectors of ATP-dependent PFK enzymes. Nevertheless, strong N-terminal amino acid sequence homology was found with ATP-PFK enzymes from other bacteria. The A. methanolica pyruvate kinase was purified over 250-fold and characterized as an allosteric enzyme, sensitive to inhibition by P(i) and ATP but stimulated by AMP. By using mutants, evidence was obtained for the presence of transketolase isoenzymes functioning in the pentose phosphate pathway and ribulose monophosphate cycle during growth on glucose and methanol, respectively.
Department of Microbiology, University of Groningen, Haren, The Netherlands.
A M
AM
Alves
G J
GJ
Euverink
H J
HJ
Hektor
G I
GI
Hessels
J
J
van der Vlag
J W
JW
Vrijbloed
D
D
Hondmann
J
J
Visser
L
L
Dijkhuizen
D039903:Actinobacteria / Q000201:enzymology* / Q000235:genetics; D000595:Amino Acid Sequence; D015971:Gene Expression Regulation, Enzymologic; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis / Q000502:physiology; D000432:Methanol / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D010427:Pentose Phosphate Pathway / Q000502:physiology; D010732:Phosphofructokinase-1 / Q000378:metabolism; D010736:Phosphoglycerate Mutase / Q000378:metabolism; D011770:Pyruvate Kinase / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014174:Transketolase / Q000235:genetics
D014174:Transketolase; D010732:Phosphofructokinase-1; D011770:Pyruvate Kinase; D010736:Phosphoglycerate Mutase; D005947:Glucose; D000432:Methanol