Carbohydrates in mammalian tryptophanyl-tRNA synthetase.

Homogeneous preparations of bovine tryptophanyl-tRNA synthetase (EC 6.1.1.2) contain monosaccharides (mannose, fucose, galactose, N-acetylglucosamine) as revealed by liquid chromatography. Their content comprises 2.5-3.0% (w/w) of the enzyme composed of two subunits (60 kDa x 2). The same set of sugars was detected in elastase and CNBr-generated fragments (with molecular masses of approx. 40 kDa and 30 kDa, respectively). It is concluded that bovine tryptophanyl-tRNA synthetase, in addition to being a metallo- and phosphoprotein, is also a glycoprotein.