Dictyopterin appears at amoebae emergence during spore germination in Dictyostelium.

Intracellular dictyopterin, which is present in reduced form, mainly as tetrahydrodictyopterin, both in vegetative cells and in starved cells, could neither be detected in dormant spores nor in unswollen or swollen activated spores. Synthesis of tetrahydrodictyopterin starts with emergence of nascent amoebae during spore germination. Tetrahydrodictyopterin levels in cell-free extracts vary as a function of the percent emerged amoebae in spore suspension. These data are consistent with a requirement for tetrahydrodictyopterin during vegetative growth.