Production and purification of mixed 14C-labelled peptides derived from plant biomass

✍ Scribed by John R. Ling; P. Bronwen Cooper; Stephen J. Parker; Ian P. Armstead

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: French
• Weight: 446 KB
• Volume: 31
• Category: Article
• ISSN: 0022-2135
• DOI: 10.1002/jlcr.2580310512

✦ Synopsis

Abstract

Procedures are described for the production and purification of ^14^C‐labelled peptides of mixed composition, derived from phytomass. Barley seeds (Hordeum vulgare) were germinated and grown in the dark for 6 days. On day 7, the seedlings were exposed to light in a ^14^CO~2~ atmosphere for 24 h. The plant leaves were harvested and their water‐soluble ^14^C‐labelled proteins extracted. These ^14^C‐proteins were partially digested by sequential incubation with pepsin, α‐chymotrypsin and trypsin. The resulting ^14^C‐labelled peptides were separated from contaminating amino acids by elution from columns of copper‐Chelex resin, and finally fractionated by gel‐filtration chromatography and assigned to groups according to molecular size. The purified ^14^C‐peptides ranged in relative molecular mass up to approximately 5,000, possessed a purity in excess of 97%, and were radiolabelled in all amino acid residues with an average specific radioactivity of 450 Bq/μmol. The methods described can be readily adapted to produce not only mixed ^14^C‐labelled peptides of any required attribute, such as molecular size or ionic charge, but also mixed ^14^C‐proteins of ^14^C‐amino acids.