  Amino acids are building-blocks of proteins, basic constituents of all
organisms and essential to life on Earth. They are present in carbonaceous
chondrite meteorites and comets, but their origin is still unknown. We present
Spitzer spectroscopic observations in the star-forming region IC 348 of the
Perseus Molecular Cloud showing the possible detections of mid-IR emission
lines consistent with the most intense laboratory bands of the three aromatic
amino acids, tyrosine, phenylalanine and tryptophan and the aliphatic amino
acids isoleucine and glycine. Based on these tentative identifications,
preliminary estimates of column densities give values 10-100 times higher for
isoleucine and glycine than for the aromatic amino acids as in some meteorites.
Potential counterparts of the strongest laboratory bands of each amino acid are
also found in the combined spectrum of 32 interstellar locations obtained in
diverse unrelated star-forming regions.
