Amino-acid biochemical properties Nonpolar Polar Basic Acidic Termination: stop codon
Standard genetic code (NCBI table 1)[1]
1st
base
2nd base 3rd
base
T C A G
T TTT (Phe/F) Phenylalanine TCT (Ser/S) Serine TAT (Tyr/Y) Tyrosine TGT (Cys/C) Cysteine T
TTC TCC TAC TGC C
TTA (Leu/L) Leucine TCA TAA Stop (Ochre)[B] TGA Stop (Opal)[B] A
TTG[A] TCG TAG Stop (Amber)[B] TGG (Trp/W) Tryptophan G
C CTT CCT (Pro/P) Proline CAT (His/H) Histidine CGT (Arg/R) Arginine T
CTC CCC CAC CGC C
CTA CCA CAA (Gln/Q) Glutamine CGA A
CTG CCG CAG CGG G
A ATT (Ile/I) Isoleucine ACT (Thr/T) Threonine AAT (Asn/N) Asparagine AGT (Ser/S) Serine T
ATC ACC AAC AGC C
ATA ACA AAA (Lys/K) Lysine AGA (Arg/R) Arginine A
ATG[A] (Met/M) Methionine ACG AAG AGG G
G GTT (Val/V) Valine GCT (Ala/A) Alanine GAT (Asp/D) Aspartic acid GGT (Gly/G) Glycine T
GTC GCC GAC GGC C
GTA GCA GAA (Glu/E) Glutamic acid GGA A
GTG[A] GCG GAG GGG G
A Possible start codons in NCBI table 1. ATG is most common.[2] The two other start codons listed by table 1 (GTG and TTG) are rare in eukaryotes.[3] Prokaryotes have less strigent start codon requirements; they are described by NCBI table 11.
B ^ ^ ^ The historical basis for designating the stop codons as amber, ochre and opal is described in an autobiography by Sydney Brenner[4] and in a historical article by Bob Edgar.[5]