Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School



Methionine was discovered in 1922 by Mueller (33) and was first known as Mueller’s acid. In 1928 Barger and Coyne (6) found that it was a methylated sulfur compound known as alpha-amino-gamma-methyl thio-butryic acid and later gave it the present shorter name of methionine. Rose and his associates (34) have shown that it is the essential sulfur amino acid and not cysteine as was formerly thought. Methionine plays an important role in the growth of plants and animals: first, as a methylating agent; second, as an amino acid essential for the building of tissue proteins; third, as a source of sulfur for the synthesis of cysteine, cysteine, and glutathione; and fourth, as a part of sulfhydryl-dependent enzymes which are vital in animal metabolism. Its labile methyl group, which is held by a covalent bond to sulfur, constitutes, together when the methyl groups from betaine and choline, a dietary “pool” of physiologically interchangeable methyl groups (18). It also aids in the healing of bone fractures (42), in the healing of wounds (40), and in the clotting of blood (43). Methionine increases the retention of nitrogen and sulfur in the bodies of dogs and rats (1) and (19). It alleviates the growth inhibition effect produced by ethionine when added to the diet (36) and affords protection against poisoning by pyridine (7). Methionine has been found to exhibit a greater number of functions than any of the other essential amino acids in biochemistry and nutrition. One commercial company is at present producing it on a large scale for poultry feeds. Since the future of methionine is bright with the prospects of new discoveries and new applications, a convenient and simple chemical means of detecting it with as much accuracy and sensitivity as possible is desirable. It was the aim of this experimental work to develop a chemical micro-method for the analysis of methionine by a modification of the McCarthy-Sullivan method. This method has been applied with satisfactory results to extracts of tissues and hydrolysates of casein, blood and liver of rat and corn.

Library of Congress Subject Headings



Includes bibliographical references (pages 33-35)



Number of Pages



South Dakota State University


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