Sub-unit structure of soluble and mitochondrial malic enzyme: demonstration of human mitochondrial enzyme in human-mouse hybrids
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Abstract:
1. Malic enzyme has been examined by starch-gel electrophoresis in human cultured fibroblasts and in 60 brain samples. The polymorphism of MEM has been confirmed and the electrophoretic pattern suggests that this enzyme, like MES, is a tetramer. 2. The appearance of the soluble and mitochondrial malic enzymes in mouse and Chinese hamster is described, and the identity of the enzymes in man, mouse and hamster has been established from a study of interspecific somatic cell hybrids. In man and in hamster MES migrates anodal to MEM, whereas in the mouse MES is relatively less anodal than MEM. 3. Segregation of human enzymes in human--mouse and human--hamster somatic cell hybrids confirms the synteny of MES and PGM3. Data from human--mouse hybrids suggest that MEM is probably not syntenic with MES is probably not syntenic with MES in man, nor is it syntenic with GPI.
Insights
Human malic enzymes (MEM and MES) exhibit polymorphism and tetrameric structure. Their genetic mapping in somatic cell hybrids reveals MEM is likely not syntenic with MES or GPI, while MES is syntenic with PGM3.
Area of Science:
- Biochemistry
- Human Genetics
- Enzyme Kinetics
Background:
- Malic enzyme (ME) exists in soluble (s-MEM) and mitochondrial (m-MES) forms.
- Understanding ME polymorphism and genetic linkage is crucial for human genetics research.
Purpose of the Study:
- To characterize the polymorphism and quaternary structure of human malic enzymes (MEM and MES).
- To determine the genetic linkage (synteny) of human MEM and MES genes using somatic cell hybrids.
Main Methods:
- Starch-gel electrophoresis was used to analyze malic enzyme polymorphism in human fibroblasts and brain samples.
- Interspecific somatic cell hybrids (human-mouse, human-hamster) were utilized to map the genes for MEM and MES.
- Electrophoretic patterns of soluble and mitochondrial malic enzymes were compared across human, mouse, and hamster species.
Main Results:
- Human malic enzyme (MEM) polymorphism was confirmed, and its electrophoretic pattern suggests a tetrameric structure, similar to MES.
- Comparative analysis of soluble and mitochondrial malic enzymes in humans, mice, and hamsters established their identity.
- Interspecific somatic cell hybrids confirmed the synteny of the MES gene with PGM3.
- Data from human-mouse hybrids indicated that the MEM gene is likely not syntenic with MES or GPI.
Conclusions:
- Human malic enzymes (MEM and MES) are confirmed to be polymorphic and likely tetrameric.
- The genetic mapping of MEM and MES using somatic cell hybrids provides insights into their chromosomal locations.
- MEM is not syntenic with MES or GPI, while MES is syntenic with PGM3, contributing to the understanding of human gene organization.