The word protein comes from Greek language meaning "of primary importance".

True to the meaning of "Proteins" there is no life without proteins or one cannot imagine life without proteins as they provide structure to the cells and body and carries out essential biological functions.  For instance hemoglobin is a protein that transports oxygen without which one cannot live.  Proteins are ubiquitous present in all-living forms such as bacteria, plants, animals and human beings.  This suggests that in the origin of life proteins played an integral part and is still continuing to play a vital role in all of the living beings.  

Proteins are very interesting as they break down to peptides and amino acids and by reverse engineering that is amino acids are used to make proteins obviously via peptides.  In other words depending on the needs amino acids are recycled to synthesize proteins or proteins broken down to amino acids to carry out essential functions of the life.  

Well, now the question is what came first, amino acids or proteins? Rationally and scientifically thinking one would say amino acids came first because the important constituents of amino acids are carbon, nitrogen, oxygen, hydrogen and sulfur (methionine, cystine, cysteine) and these are abundantly available in the nature.  It is possible that the first amino acid that was formed in the evolutionary process is Glycine. This could be one of the reasons as to why astronomers are looking for glycine in space and in 1994 to 2004 they have claimed that they found Glycine in the space.  However, these claims could not be confirmed later on.

The simplest amino acid of all the 20 amino acids is glycine and more than one third of collagen (structural protein) is made up of glycine.  It is also present in other proteins such as Cytochrome C, Hemoglobin, etc., that carries out important/ essential biological functions.

The simplest amino acid Glycine, HO₂CCH₂NH₂