Reaction of selenomethionine with o-benzoquinone

✍ Scribed by M.N. Gupta; R. Gopinath; K. Raju

• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 334 KB
• Volume: 118
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(81)90183-4

✦ Synopsis

A new reaction of selenomethionine with o-benz~uinone is described. This reaction can be used to distinguish between methionine and selenomethionine.

Selenium is known to occur in many biological systems (l-3). It is invariably associated with proteins or amino acids (1). In common plants most of the selenium is present as selenomethionine

(1). However, in most of the cases proper characterization of the selenium-containing moieties is not possible, though lately some efforts have been made in this direction (1,4). One limiting factor is that the chemistry of the selenoamino acids is relatively less investigated than that of the sulfur-amigo acids. Further more, there is a paucity of analytical procedures which can distinguish between selenium-containing amino acids or peptides from the corresponding sulfur analogs (2). We describe here a derivative of selenomethionine which can be easily identified because of its spectral properties. It is also possible to distinguish between methionine and setenomethionine using this reaction.

o-Benzoquinone reacts with methionine and methionine-containing proteins to give a sulfonium compound (5-7). We have found that at lower pH (than necessary in case of methionine), selenomethionine also undergoes a similar reaction. Thus, using this reaction, it should be possible to detect selenomethionine in the presence of methionine.

' The person to whom all ~rres~ndence should be directed.

* Formerly registered for Ph.D. degree at I.I.T. Delhi.