Oxidation of C1-compounds in Pseudomonas C

Area of Science:

• Microbiology
• Biochemistry
• Metabolic Pathways

Background:

• Pseudomonas C utilizes methanol as a sole carbon and energy source.
• Methanol metabolism involves methanol dehydrogenase and formaldehyde oxidation.

Purpose of the Study:

• To investigate the metabolic fate of formaldehyde in methanol-grown Pseudomonas C.
• To elucidate the pathways involved in formaldehyde carbon oxidation to CO2.

Main Methods:

• Enzyme activity assays for methanol dehydrogenase, formaldehyde dehydrogenase, and formate dehydrogenase.
• Radiolabeling studies using [14C]formaldehyde and [14C]glucose 6-phosphate.
• Analysis of enzyme activities including hexulose phosphate synthase and dehydrogenases.

Main Results:

• Methanol-grown Pseudomonas C extracts exhibit methanol dehydrogenase activity.
• D-ribulose 5-phosphate enhances formaldehyde oxidation to CO2.
• A cyclic pathway, predominant over formate oxidation, metabolizes formaldehyde carbon to CO2.

Conclusions:

• Methanol-grown Pseudomonas C employs a cyclic pathway for formaldehyde oxidation to CO2.
• This cyclic pathway involves hexulose phosphate synthase and other key enzymes.
• Formate also serves as an intermediate, but the cyclic pathway is the primary route.