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APPENDIX 



MOLECULAR STRUCTURES 

 OF IMPORTANT BIOLOGICAL COMPOUNDS 



The Twenty Amino Acids Found in Proteins 



GLYCINE (gly) 



CH 2 — COOH 



NH, 



ALANINE (ala) 



CH, — CH — COOH 



NH- 



VALINE (val) 



CH, — CH — CH— COOH 



CH 3 NH 2 



ISOLEUCINE(ile) LEUCINE (leu) 



CH 3 — CH 2 — CH— CH — COOH CH3 — CH — CH 2 — CH — COOH 



CH 3 NH 2 



CH- 



NH- 



PROLINE (pro) 



CH- 



CH- 



■N- 

 H 



CH- 



,CH— COOH 



SERINE (ser) 



CH,— CH — COOH 



I I 



OH NH, 



THREONINE (thr) 



CH,— CH — CH— COOH 



I I 



OH NH, 



ASPARTIC ACID (asp) 



HOOC — CH, — CH— COOH 



I 

 NH 2 



GLUTAMIC ACID (glu) 



HOOC — CH,— CH,— CH— COOH 



I 

 NH, 



CYSTEINE (cys) 



CH 2 — CH— COOH 



SH NH- 



METHIONINE (met) 



CH 3 — S— CH 2 -CH 2 -CH — COOH 



NH, 



