3-phosphoglycerate kinase from Hydrogenomonas facilis

Area of Science:

• Biochemistry
• Microbiology

Background:

• Phosphoglycerate kinase is a key enzyme in glycolysis and gluconeogenesis.
• Understanding its regulation in bacteria like Hydrogenomonas facilis is crucial for metabolic studies.

Purpose of the Study:

• To investigate the levels and activity of phosphoglycerate kinase in Hydrogenomonas facilis under different growth conditions.
• To purify and characterize the enzyme's kinetic properties and regulatory mechanisms.

Main Methods:

• Cell growth on various carbon sources (fructose, lactate, succinate, glutamate).
• Enzyme extraction and purification (300-fold purification).
• Determination of specific enzyme activities, Michaelis constants (Km), and inhibition by adenosine monophosphate (AMP).

Main Results:

• Phosphoglycerate kinase levels were relatively constant across different growth conditions.
• Purified enzyme showed specific activity of 90 µmol/min/mg protein.
• Km values for ATP, 3-phosphoglycerate, and Mg++ were determined.
• Adenosine monophosphate (AMP) caused significant inhibition (23% at AMP/ATP ratio of 2.4).

Conclusions:

• Phosphoglycerate kinase in Hydrogenomonas facilis exhibits stable expression.
• The enzyme's kinetic properties and inhibition by AMP suggest regulatory roles in cellular metabolism.
• No evidence for an alternative ATP-dependent pathway involving 3-phosphoglycerate was found.