  Hydroxylamine (NH$_{2}$OH) and methylamine (CH$_{3}$NH$_{2}$) have both been
suggested as precursors to the formation of amino acids and are therefore of
interest to prebiotic chemistry. Their presence in interstellar space and
formation mechanisms, however, are not well established. We aim to detect both
amines and their potential precursor molecules NO, N$_{2}$O and CH$_{2}$NH
towards the low-mass protostellar binary IRAS 16293--2422, in order to
investigate their presence and constrain their interstellar formation
mechanisms around a young Sun-like protostar. ALMA observations from the
unbiased, high angular resolution and sensitivity Protostellar Interferometric
Line Survey (PILS) are used. Spectral transitions of the molecules under
investigation are searched for with the CASSIS line analysis software. CH$_2$NH
and N$_{2}$O are detected for the first time towards a low-mass source, the
latter molecule through confirmation with the single-dish TIMASSS survey. NO is
also detected. CH$_{3}$NH$_{2}$ and NH$_{2}$OH are not detected and stringent
upper limit column densities are determined. The non-detection of
CH$_{3}$NH$_{2}$ and NH$_{2}$OH limits the importance of formation routes to
amino acids involving these species. The detection of CH$_{2}$NH makes amino
acid formation routes starting from this molecule plausible. The low abundances
of CH$_2$NH and CH$_{3}$NH$_{2}$ compared to Sgr B2 indicate that different
physical conditions influence their formation in low- and high-mass sources.
