The other protein that makes up gluten, glutenin, is generally not considered a celiac disease trigger, although it may play a part. Further research is required in this area of gluten and the negative aspects of health.
In other words, it is part of what makes up gluten found in wheat, but in other related grains also. Not only is it part of gluten, more specifically, it is the nasty part of gluten and can trigger several different diseases, as explained later in this article.
There are several types of gliadin, classified according to solubility in different solutions. They also differ in how they trigger certain diseases.
All of the above types can trigger celiac disease.
This is a form of gliadin treated with an acid or an enzyme. Normally, gliadins are not soluble in water. Modern food processing being what it is, some manufacturers want it to disolve in water anyhow, and deamidated gliadin allows this. This could trigger gluten allergy symptoms.