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Localization of pyruvate carboxylase in organic acid-producing Aspergillus strains
A Bercovitz1, Y Peleg, E Battat
1Department of Applied Microbiology, Hebrew University, Jerusalem, Israel.
Abstract:
The localization of pyruvate carboxylase (cytosolic or mitochondrial) was studied in nine different Aspergillus species (14 strains). In some species (A. aculeatus, A. flavus, A. foetidus, A. nidulans, A. ochraceus, and A. sojae), the pyruvate carboxylase activity could be detected only in the cytosolic fraction of the cells. Pyruvate carboxylase has been found only in the mitochondrial fraction of two strains of Aspergillus wentii. In Aspergillus oryzae and in five strains of Aspergillus niger, pyruvate carboxylase activity was detected both in the mitochondrial fraction and in the cytosol. There was no quantitative or qualitative correlation between the activities of pyruvate carboxylase in the mitochondrial and cytosolic fractions of the cells and the ability of the various Aspergillus strains to accumulate different organic acids.
Insights
Pyruvate carboxylase localization varies across Aspergillus species, found in cytosol, mitochondria, or both. This enzyme
Area of Science:
- Biochemistry
- Molecular Biology
- Mycology
Background:
- Pyruvate carboxylase is a key enzyme in metabolism.
- Its cellular localization (cytosolic or mitochondrial) can impact metabolic pathways.
- Understanding its distribution in Aspergillus species is crucial for fungal metabolism studies.
Purpose of the Study:
- To investigate the subcellular localization of pyruvate carboxylase in various Aspergillus species.
- To determine if pyruvate carboxylase activity correlates with organic acid accumulation in Aspergillus.
Main Methods:
- Enzyme activity assays were performed on cytosolic and mitochondrial fractions.
- Fourteen strains from nine Aspergillus species were analyzed.
- Organic acid accumulation was quantified.
Main Results:
- Pyruvate carboxylase activity was exclusively cytosolic in A. aculeatus, A. flavus, A. foetidus, A. nidulans, A. ochraceus, and A. sojae.
- Activity was exclusively mitochondrial in two strains of A. wentii.
- Activity was found in both fractions in A. oryzae and five strains of A. niger.
Conclusions:
- Pyruvate carboxylase exhibits diverse subcellular localization patterns within Aspergillus species.
- No correlation was observed between pyruvate carboxylase localization/activity and organic acid accumulation.