Definition of Amino acid symbols
Amino acid symbols: Symbols that stand for the amino acids, the building blocks of protein. Each amino acid has both a three-letter symbol and a single-letter symbol. For example, the three-letter and single-letter symbols for alanine are Ala and A. The three-letter symbols (such as Ala) are much more widely used than the single letter ones (such as A).
Therefore, the following list is limited to the three-letter symbols and is further limited to those 20 alpha-amino acids specified by the genetic code:
These three-letter symbols for amino acids are used not only to refer to an individual amino acid but also to present the amino acid sequence of a polypeptide or a protein. For example, part of the sequence of insulin reads: Gly-Ile-Val-Glu-Gln-Cys-Cys-Ala-Ser-Val. The N-terminal residue of the polypeptide or protein is by convention always on the left and the sequence reads from left-to-right toward the C-terminal residue of the polypeptide or protein.
Last Editorial Review: 6/14/2012
Back to MedTerms online medical dictionary A-Z List
Need help identifying pills and medications?
- Allergic Skin Disorders
- Bacterial Skin Diseases
- Bites and Infestations
- Diseases of Pigment
- Fungal Skin Diseases
- Medical Anatomy and Illustrations
- Noncancerous, Precancerous & Cancerous Tumors
- Oral Health Conditions
- Papules, Scales, Plaques and Eruptions
- Scalp, Hair and Nails
- Sexually Transmitted Diseases (STDs)
- Vascular, Lymphatic and Systemic Conditions
- Viral Skin Diseases
- Additional Skin Conditions