[ Submit a Question, Answer or Critique]
From: m. ballard
Date: 06 Feb 2004
Time: 18:16:15 -0500
Remote Name: 172.16.11.77
Actually there are 20 standard or primary amino acids. The other/extra amino acids are all derivatives of the original 20 with extra functional groups added on for a particular function. There are many example on pg121-122 that show the structure and the original amino acid it was derived from. Moreover, the reason they are so limited in the human body is because of the need for them. There are only a few special cases where this occurs. And in these cases they are still derived from original amino acids. Furthermore, viruses can make use of these modification on amino acids for the purpose of recognition or destruction.