224 



AMINO ACIDS, PEPTIDES AND PROTEINS 



CO„H 

 I 2 

 H-NCH 

 2 I 

 HOCH 

 I 

 CH, 



CO„H 

 I 2 

 H,NCH 



'^ I 

 CH 

 I 

 CH OH 



CO„H 

 I - 

 H„NCH 

 2 I 

 CH, 



CH2SH 



COoH 

 I 



H„NCH 

 "^ I 

 CH^ 



CH2SCH 



L-THREONINE 



COpH 

 I 

 H,NCH 

 "^ I 

 CH, 

 I ^ 

 CO^H 



L-ASPARTIC 

 ACID 



L-HOMOSERINE 



CO,H 



H,NCH 

 ^ I 

 CH_ 

 I ^ 

 HC = 



/5'- L-ASPARTIC 

 ALDEHYDE 



L-HOMOCYSTEINE 



CO,H 

 I 2 

 HgNCH 



L-METHIONINE 



CO,H 

 I '- 

 H^NCH 

 2 I 

 CH, 

 I ^ 

 CH, 

 I ^ 

 CH, 

 I ' 

 CHgNHg 



MESO-<<, f - DIAMINO- 

 PIMELIC ACID 



L- LYSINE 



ANALOGOUS 

 TO VALINE 



CH„ 



/ 



CH^ 



CH, 



^2 



/ 



CH CO,H 



N 

 H 



L-PIPECOLIC ACID 



CH 

 I 3 

 HC-CHgCHj 



H,NCH 

 '^ I 

 COgH 



L- ISOLEUCINE 



LEUCINE 



FIGURE 10-1. AMINO ACID PATHWAYS 



