PRIMING REACTIONS 



217 



CHs CH3 



\/ 

 CH 



CH3 CHs CH3CH3 CH3 CH3 CH3 CH2 



CHa- 



I 



C: 

 I 



s 



CH CH 



CoA I — CO2 I 



CH2-< C = O- 



O 



C = O 



I 

 COOH 



COOH 



CH 



I 



-*-c = o 



I 



s 



I 



CoA 



CH 



O 



+ CoA 



1 — COa 

 COOH 



CH3 CH3 CH2 



\/ 

 CH 



I 



c = o 



I 



s 



I 



CoA 



CH3 



o 



CoA 



isovalers'l- 

 CoA' 



Ik 



CH3 CHs 



\/ 

 C 



II 

 CH 



I 



c = o 



I 



s 



a-ketoiso- a-ketoiso- isobutyryl- 

 caproic acid valeric acid CoA 



a-keto- 



j3-methyl,valeric 



acid 



L-methyl-butyryl- 



i CoA 



CHs CH3 



\/ 

 CH 



I 

 CH2 



I 

 CHNH2 



I 

 COOH 



CH3 CHs CHs CH2 CHs CHa — CHs CHs 



CH2 



CH3 



CH 



I 

 CHNH2 



I 

 COOH 



\aline 



CoA 



senecioyl-CoA Leucine 



CHs CHs 



\/ 

 COH 



I 

 CH2 



I 



c = o 



I 



s 



I 



CoA 



^-hydroxv-iso\alervl-CoA 



I 



COOH 



I 

 CH2 



I 

 CH3COH • 



I 

 CH2 



I 



c = o 



CoA 

 ^-hydroxy-;S-methyI-glutary-CoA 



r 



CHs CHs 



I I 



c = o c = o 



I I 



CH2 + s 



I I 



COOH CoA 



acetoacetic acetyl- 

 acid CoA 



C 



I 



c = 



I 



s 



I 



CoA 



O 



CH 



I 

 CHNH2 



I 

 COOH 



Methacryl-CoA Isoleucine 



CHs CH2OH 



\/ 

 CH 



c = o 



S 



I 

 CoA 



C 



I 



c = o 



I 



s 



I 



CoA 



tiglyl-CoA 



' + H2O 

 >| 

 CHs CHOH — CHs 



\/ 

 CH 



1 



c = o 



I 



s 



I 



CoA 



a-methyl-j3-hydroxy- 

 butyryl-CoA 



i^DPN + 

 VDPNH 



CHs CO — CH3 



\/ 

 CH 



c = o 



s 



I 



CoA 

 a-methyl-acetoacetyl-CoA 



Fig. 50 (after Coon) — Degradation of leucine, valine and isoleucine. 



