US EPA

1141292 

Technical Report 

Kinetics and pathways of methanol metabolism 

Rietbrock, N 

1969 

NIOSH/00139852 

263 

88-105 

German 

4389910 

The kinetics and mechanism of methanol (67561) metabolism are reviewed. Methanol is more closely related to water in its chemical and physical properties than other aliphatic alcohols. The kinetics of methanol metabolism are discussed. The elimination of methanol follows a biphasic kinetic mechanism. Initially, the reaction rate increases reaching a maximum after 24 hours. The rate then decreases until after 72 hours and it begins to follow a simple exponential decay law. The metabolic pathways of methanol are discussed. Oxidation of methanol by alcohol-dehydrogenase and alcohol-catalase is considered. Oxidation of methanol by microsomal enzymes is discussed. The elimination of formic-acid (64186) is considered. Formic-acid formed as a metabolite, is the actual toxic agent in cases of methanol intoxication. The factor that determines the toxicity of methanol is the rate of elimination of formic-acid. Research on dogs that have a folic-acid deficiency has shown a correlation between the plasma concentration of formate and the extent of metabolic acidosis, the main symptom of methanol poisoning. The activation of formic-acid by folate coenzymes is discussed. The author notes that the oxidative steps in the folate cycle during methanol intoxication have not been thoroughly investigated. (German)