Search for glycine in the solar type protostar IRAS 16293-2422

We report the first search for line emission from one of the simplest amino acids, glycine, from a solar type protostar, IRAS16293-2422. Previous searches for glycine have been carried out on bright massive star formation regions, so far without success. Recent observations show that although less luminous, solar type protostars also harbor complex molecules and may even be more favorable than massive protostars for the formation and survival of complex molecules. We did not detect any emission associated with glycine from IRAS16293-2422. Based on these observations, we claim that the glycine column density is less than ~ 5 x 10¹² cm^-2. Using information we have on the structure of the envelope surrounding IRAS16293-2422, we derive an upper limit to the glycine abundance of ~ 1 x 10^-10 in the cold outer envelope and ~ 7 x 10^-9 in the hot core, respectively. These observations challenge recent theoretical estimates of glycine abundance in solar type protostars.