<p>This entry represents saccharopine dehydrogenase and homospermidine synthase.</p><p>Saccharopine reductase (SR) <db_xref db="EC" dbkey="1.5.1.10"/>) catalyses the condensation of l-alpha-aminoadipate-delta-semialdehyde (AASA) with l-glutamate to give an imine, which is reduced by NADPH to give saccharopine [<cite idref="PUB00053404"/>]. In some organisms this enzyme is found as a bifunctional polypeptide with lysine ketoglutarate reductase (PF). Saccharopine dehydrogenase can also function as a saccharopine reductase.</p><p>Homospermidine synthase proteins (<db_xref db="EC" dbkey="2.5.1.44"/>). Homospermidine synthase (HSS) catalyses the synthesis of the polyamine homospermidine from 2 mol putrescine in an NAD<sup>+</sup>-dependent reaction [<cite idref="PUB00012373"/>].</p>