Purification and partial sequence of an alpha 3-gliadin.

Coeliac disease (gluten enteropathy) is associated with a damaged gut mucosa displaying degraded villi and poor absorption of nutrients. The major symptoms are emaciation, swollen abdomen, poor growth, vomiting, diarrhoea and steatorrhea [I]. The condition affects 1 in 1850 individuals in the UK although the world-wide incidence is variable and depends upon the dietary use of wheat and similar cereals. Coeliac disease is caused by an intolerance to the gluten content of cereal flours [ I ] . Gluten contains approximately equal portions of glutenin and gliadin proteins; only gliadins are pathogenic to susceptible individuals. Starch gel electrophoresis (SGE) separates gliadins into a-, p-, o and y-fractions, in order of decreasing electrophoretic mobility [2]. More recently, gliadins have been classified according to their sizes, composition and amino terminal sequences [3]. The predominant groups in this classification are the sulphur-rich a@and y-gliadins and the sulphur-poor o-gliadins. The a-gliadin fraction, comprising up to about 50 distinct polypeptides, is the most pathogenic. We recently reported the preparation of discrete a-gliadins using RP-HPLC [4] as a preliminary to investigating their structure. The utility of these methods has recently been confirmed [ S ] .