The advantage of the direct uptake of amino acids is in the energy
saved that would otherwise be required for synthesizing C structural
components. And the advantage of the MIT route is that only one transporter
system for N uptake is required (Geisseler et al., 2010). The first
step of both routes is the breakdown of polymeric N compounds by extracellular
depolymerases in soil (e.g. protease) and the release of soluble
amino acids, small peptides or amino sugars (Geisseler et al., 2010).
When the MIT route is dominant, protease activity and gross N