150 



H 



HO 



GENERAL BIOCHEMISTRY 

 CHsOPO.r 



0\ GH2OOCR 



\ H 1 



\ CHOOCR' 



H / CH20P03CH2CH2N+(CH3)3 



H 

 OH 



OH 



H OH 



glucose-6-phosphate 



a lecithin 



CHaCOOPOs^ 



acetyl phosphate 



H03POP03= 



pyrophosphate 



The i:)h()sphatases are important in the digestion of compounds of 

 these types, in the maintenance of a sufficient supply of inorganic 

 phosphate, and in the metaboiic reactions of phospliorylated materials. 



Amidases and Peptidases 



These enzymes split amides and peptides of various kinds. They 

 are widespread and act on natural amides and peptides but not 

 ordinarily on proteins. The specificity may be sharp or slight, and they 

 play important roles at the end of digestive processes yielding very 

 small peptides, amino acids, and ammonia. As an example, urease is 

 distributed among plants, animals, and microorganisms and hydrolyzes 

 urea into ammonia and carbonic acid. 



Oxidases 



Among the oxidation-reduction enzymes the oxidases are especially 

 important to all aerobic cells because certain of these enzymes provide 

 for the use of molecular oxygen as an oxidizing agent. This arrange- 

 ment is based on different enzymes in different cells. A number of 

 plants contain oxidases catalyzing the oxidation of certain catechol 

 derivatives according to: 



O 



OH II O 



/-^OH 



+ O2 



eiizyiiie 



-> L 



-f 2H2O 



R 



R 



The enzymes of this group are known by many names, including 

 tyrosinase and catecholase. The product of the reaction, a quinone, 

 is reduced by some other cellular material and then undergoes another 



