PROSITE documentation PDOC00350

Cereal trypsin/alpha-amylase inhibitors family signature

The seeds of cereals contain numerous serine proteases and α-amylase inhibitors. These inhibitors can be grouped into families based on structural similarities. The cereal trypsin/α-amylase inhibitor family [1,2] consists of proteins of about 120 amino acids which contain 10 cysteine residues, all of which are involved in disulfide bonds. Some of these inhibitors are specific to trypsin, others to α-amylase, and a few are bifunctional. The schematic representation of the structure of these inhibitors is shown below:

                       +----------------------------+
           +----------+|   +-+                      |
    *******|****      ||   | |                      |
  xxCxxxxxxCxxxCxxxxxxCCxxxCxCxxxxxxxxxxxxxCxxxxxxxxCxxxxxxxCxxxx
    |          |                           |                |
    |          +---------------------------+                |
    +-------------------------------------------------------+

'C': conserved cysteine involved in a disulfide bond.
'*': position of the pattern.

This family of proteins also includes a number of seed allergenic protein from rice [3].