Weak acids physiologic significance

Functional Groups That Are Weak Acids Have Great Physiologic Significance... 

This lack in response to small effector molecules may well be related to the profound differences in molecular structure between the two types of carboxylases (23). Equally important for regulation, the animal fatty acid synthetases from whatever source (liver, adipose tissue, brain or mammary gland) produce free fatty acids rather than fatty acyl-CoA derivatives. Free fatty acids inhibit the animal fatty acid synthetases only very weakly if at all. This means that the synthetase itself does not produce a feedback inhibitor sensu strictu if, indeed, palmitoyl-CoA regulation of acetyl-CoA carboxylase and other lipogenic enzymes should prove to be physiologically significant. 

Amines like ammonia are weak bases They are however the strongest uncharged bases found m significant quantities under physiological conditions Amines are usually the bases involved m biological acid-base reactions they are often the nucleophiles m biological nucleophilic substitutions... 

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