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Ontogenetic development of a 5-methyltetrahydrofolate requiring enzyme in rats and mice
Abstract:
Developmental characteristics of 5-methyltetrahydrofolate requiring N-methyltransferase (5 MT-NMT) have been studied in rats and mice and compared to the development pattern of marker enzymes. In rat and mouse brain, the 5 MT-NMT activity expressed in units per mg protein, was found to decrease rapidly during the first five days after birth and then more slowly, whereas two other enzymes, dopa-decarboxylase and histamine N-methyltransferase increased gradually during maturation. In kidney, the ontogenetic development of 5 MT-NMT was first characterized by an increasing activity from birth until a different age, depending on the species, and then followed by an abrupt decline. In contrast to this, histamine N-methyltransferase activity in mouse kidney was about 60 times higher at maturity than at birth. When the enzyme activities are expressed in units per g tissue, the changes in the course of the development of 5 MT-NMT were less apparent, but in any way differed markedly from those of dopa-decarboxylase and histamine N-methyltransferase. The results suggest that 5 MT-NMT does not behave as a synaptosomal or perhaps even as a neuronal enzyme. Although its physiological role remains to be elucidated, it must have a more general function in the cellular economy than merely N-methylating biogenic amines.
Insights
The developmental pattern of 5-methyltetrahydrofolate requiring N-methyltransferase (5 MT-NMT) differs from marker enzymes in rat and mouse brains and kidneys. This suggests 5 MT-NMT has a broader cellular function beyond methylating biogenic amines.
Area of Science:
- Biochemistry
- Developmental Biology
- Neuroscience
Background:
- Understanding the ontogeny of enzymes is crucial for elucidating their physiological roles.
- 5-methyltetrahydrofolate requiring N-methyltransferase (5 MT-NMT) is an enzyme with an uncharacterized developmental trajectory.
- Comparison with established marker enzymes aids in understanding enzyme function and localization.
Purpose of the Study:
- To investigate the developmental characteristics of 5 MT-NMT in rat and mouse brains and kidneys.
- To compare the ontogenetic pattern of 5 MT-NMT with marker enzymes like dopa-decarboxylase and histamine N-methyltransferase.
- To infer the potential physiological role and cellular localization of 5 MT-NMT based on its developmental profile.
Main Methods:
- Enzyme activity assays were performed on brain and kidney tissues from rats and mice at various developmental stages.
- Enzyme activities were measured and expressed per mg of protein and per g of tissue.
- Developmental patterns of 5 MT-NMT were compared with those of dopa-decarboxylase and histamine N-methyltransferase.
Main Results:
- In rat and mouse brains, 5 MT-NMT activity decreased postnatally, while dopa-decarboxylase and histamine N-methyltransferase activities increased.
- Kidney 5 MT-NMT activity showed an initial increase followed by a decline, contrasting with the significant increase in histamine N-methyltransferase activity.
- When expressed per gram of tissue, the developmental changes in 5 MT-NMT were less pronounced but still distinct from other enzymes.
Conclusions:
- The distinct developmental pattern of 5 MT-NMT suggests it is not exclusively a synaptosomal or neuronal enzyme.
- The findings indicate that 5 MT-NMT likely serves a more general function in cellular metabolism.
- Further research is needed to fully elucidate the physiological significance of 5 MT-NMT.