276 BACTERIOLOGICAL CHEMISTRY 



down to give a mixture of dihydroxyacetone mono- 

 phosphate and 3-phosphoglyceraldehyde : — 



CH2O.PO3H2 CH0O.PO3H2 



I I 



CO CO 



I 1 



HOCH ^^ CH2OH 



I + 



HCOH CHO 



I I 



HCOH HCOH 



I I 



CH2O.PO3H2 CH2O.PO3H2 



The dihydroxyacetone phosphate is converted into 

 3-glyceraldehyde phosphate by the enzyme isomerase : — 



CH2O.PO3H2 CH2O.PO3H2 



I I 



CO ^=^ CHOH 



I • I 



CH2OH CHO 



The 3-glyceraldehyde phosphate, reacting with inorganic 



phosphate and co -enzyme I, is oxidised to 2 : 3-diphospho- 



glyceric acid whilst the co -enzyme is reduced (see 



p. 203) :— 



CHO COOH 



I Trio.se- | Dihydro- 



CHOH + H3PO4 + Co-enzyme I — > CHO.PO3H2 + co-enzyme 



1 phosphorvlase | I 

 CH2O.PO3H2 ^ CH2O.PO3H2 



2 : 3-Diphosphoglyceric acid then loses phosphate to 

 adenosine diphosphate :— 



2 : 3-dipliosphoglyceric acid + adenosine diphosphate > 



3-phosphoglyccric acid + adenosine triphosphate 



3-Phosphoglyceric acid is converted by the enzyme, 

 phosphoglyceromutase, to 2-phosphoglyceric acid and 

 this by the enzyme, enolase, to phosphopyruvic acid : — 



COOH COOH COOH 



CHOH — =^ (^HO.POgHo .— ^ C.O.PO3H2 + H2O 



I I " II 



CHaO.POgHa CH2OH CH, 



(.■i-|)liosi)lioglyccric uci.l; (:.'-iili(»sphog:Iyct.'ric' m-i.t) (pliosijliopyruvi.- acid) 



