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NATURE OF THE ENDOTOXIN-INACTIVATING PRINCIPLE IN GUINEA-PIG LIVER
Abstract:
Corwin, L. M. (Walter Reed Army Medical Center, Washington, D.C.), and W. E. Farrar, Jr. Nature of the endotoxin-inactivating principle in guinea-pig liver. J. Bacteriol. 87:832-837. 1964.-Guinea-pig liver preparations inactivate Serratia marcescens endotoxin as assayed in chick embryo. The activity is optimal at pH 6.5 to 7.0 and 8.5 to 9.0. Mitochondria and the supernatant fraction containing microsomes possess activity. Mitochondria are only active at the acid pH optimum. The activity of acetone powder extracts of mitochondria is enhanced by adenosine triphosphate and nicotinamide adenine dinucleotide, whereas the mitochondria themselves are also activated by malate. It was concluded that the enzymes which inactivate endotoxin involve fatty acid activation and oxidation. Such a finding suggests that the lipid moiety of endotoxin is required for toxicity.
Insights
Guinea-pig liver preparations inactivate endotoxin via enzymes involving fatty acid activation and oxidation. This suggests the lipid component of endotoxin is crucial for its toxicity.
Area of Science:
- Microbiology
- Biochemistry
Background:
- Endotoxins, particularly from Serratia marcescens, pose a significant challenge in biological systems.
- The liver is a key organ involved in detoxification processes.
Purpose of the Study:
- To investigate the nature of the endotoxin-inactivating principle present in guinea-pig liver.
- To identify cellular fractions and enzymatic pathways responsible for endotoxin inactivation.
Main Methods:
- Assay of endotoxin inactivation using chick embryo.
- Fractionation of guinea-pig liver preparations (mitochondria, supernatant).
- Analysis of enzyme activity under varying pH conditions and with cofactors like ATP, NAD, and malate.
Main Results:
- Guinea-pig liver preparations demonstrated inactivation of Serratia marcescens endotoxin.
- Optimal inactivation occurred at pH 6.5-7.0 and 8.5-9.0.
- Both mitochondrial and microsomal fractions showed activity, with mitochondria active at acidic pH.
- Mitochondrial enzyme activity was enhanced by adenosine triphosphate, nicotinamide adenine dinucleotide, and malate.
Conclusions:
- The enzymes responsible for endotoxin inactivation involve fatty acid activation and oxidation.
- The lipid moiety of endotoxin is suggested to be essential for its toxic effects.
