HISTORY OF THE DISCOVERY OF THE CONJUGATION MECHANISMS

Abstract

This chapter focuses on the history of the discovery of the conjugation mechanisms. The majority of the biochemical reactions called conjugations were discovered during the 19th century, largely through the study of the composition of normal and pathological urines. Conjugates are the end products of the metabolism of many natural and foreign chemicals, and it seems logical in view of the methods then used that they should have been found before the oxidation, reduction, and hydrolysis products of foreign compounds that are usually intermediates in the formation of conjugates. The terms conjugated, conjugation, and conjugate have arisen from the use of the German word gepaart to describe the indigo-forming substances in urine. At the present time, two variants of this word are used, namely, detoxication and detoxification with possibly a shade of difference in meaning, the former being the process of reducing toxicity and the latter the capacity for reducing toxicity. Nearly all the enzyme systems involved in conjugation reactions have natural substrates, and all the conjugating agents have roles in normal intermediary metabolism apart from those involving foreign compounds. The major conjugation reactions are relatively few in number, and the conjugating agents are derived mainly from the animal's carbohydrate and amino acid sources.