Weak acids group 15 oxoacids

Phosphoric acid, sulfuric acid, and the hydrogen sulfate ion are members of a group of acids known as oxoacids. An oxoacid has a central atom bonded to a variable number of oxygen atoms and OH groups. Except for the three oxoacids shown in Table (sulfuric acid, nitric acid, and perchloric acid), all of the oxoacids described in this textbook are weak acids. Chapter 17 describes in detail the chemistry of strong and weak acids, including carboxylic acids and oxoacids. 

All above-mentioned experiments have made a basis for the construction of the oxoacidity scale of melts based on alkali metal halides at 700 °C [195]. This scale is presented in Fig. 1.3.1. The studied ionic melts may be divided into three groups. The first group includes the melts of weak acidity, such as the KCl-NaCl equimolar mixture, the ternary CsCl-KCl-NaCl eutectic possessing the p/csCi-KCi-NaCi,s which is equal to —0.1, and the Nal melt. 

Aspartate aminotransferase catalyses the transfer of the NH2 group between aspartic acid and 2-oxoacids via the intervention of a pyridoxal coenzyme. The kinetically significant step, a 1,3-proton transfer, is thought to involve lysine-258 in a proton relay system (Scheme 18) replacement of lysine-258 with an alanine residue by site-directed muta-tion Q yields a mutant enzyme which is only weakly active but which can have activity restored by added amines (Scheme 18). 

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