The amount of folate compounds rapidly increased during germination of the pea. An especially high increase was observed 2 days after sowing, with a continuously increasing content during germination. Dihydrofolate synthetase [EC 6.3.2.12] activity also increased with the in-crease in the amount of folate compounds, and the maximum activity was observed at 6 days after sowing in the dark and at 8 days after sowing in the light. The dhydrofolate synthetase was localized mostly in the mitochondrial fraction and it was easily extracted from the cell particles by osmotic shock. A similar localization was also observed in spinach leaves. The enzyme which was extracted from the isolated mitochondria was relatively stable in comparison with that extracted from whole cells.
