  The search for the simplest amino acid, glycine (NH$_{2}$CH$_{2}$COOH), in
the interstellar medium (ISM), has become a never-ending story for
astrochemistry and astrophysics researchers because that molecule plays a
possible connection between the Universe and the origin of life. In the last
forty years, all searches for NH$_{2}$CH$_{2}$COOH in the ISM at millimeter and
submillimeter wavelengths have failed. Since the detection of
NH$_{2}$CH$_{2}$COOH in the ISM was extremely difficult, we aimed to search for
the possible precursors of NH$_{2}$CH$_{2}$COOH. Earlier, many laboratory
experiments have suggested that methylamine (CH$_{3}$NH$_{2}$) plays an
important role in the ISM as a possible precursor of NH$_{2}$CH$_{2}$COOH.
After spectral analysis using the local thermodynamic equilibrium (LTE) model,
we identified the rotational emission lines of CH$_{3}$NH$_{2}$ towards the hot
molecular core G358.93$-$0.03 MM1 using the Atacama Large
Millimeter/Submillimeter Array (ALMA). The column density of CH$_{3}$NH$_{2}$
towards the G358.93$-$0.03 MM1 was estimated to be
(1.10$\pm$0.31)$\times$10$^{17}$ cm$^{-2}$ with an excitation temperature of
180.8$\pm$25.5 K. The fractional abundance of CH$_{3}$NH$_{2}$ with respect to
H$_{2}$ towards the G358.93$-$0.03 MM1 was (8.80$\pm$2.60)$\times$10$^{-8}$.
The column density ratio of CH$_{3}$NH$_{2}$ and NH$_{2}$CN towards
G358.93$-$0.03 MM1 was (1.86$\pm$0.95)$\times$10$^{2}$. The estimated
fractional abundance of CH$_{3}$NH$_{2}$ towards the G358.93$-$0.03 MM1 agrees
fairly well with the previous three-phase warm-up chemical modelling abundance
of CH$_{3}$NH$_{2}$. We also discussed the possible formation mechanism of
CH$_{3}$NH$_{2}$, and we find that CH$_{3}$NH$_{2}$ is most probably formed via
the reactions of radical CH$_{3}$ and radical NH$_{2}$ on the grain surface of
G358.93$-$0.03 MM1.
