Assertion: polypeptide's amino acid | /r/HasProperty | added
Facets:
Source sentences:
text: Living cells contain just twenty different kinds of amino acids, to which one more amino acid has to be added; that is Seleno-Cysteine; so, the total number of amino acids in biosystem is 21; which act as building blocks of protein chains; not only that amino acids are involved in basic cellular metabolism.