The 20 kDa precursor of hevein and its C-terminal 14 kDa domain have been isolated. Sequence analysis of the C-terminal tryptic peptides of these proteins and comparison with the cDNA sequence indicate that they represent mature forms from which a C-terminal propeptide, possibly involved in vacuolar targeting, has been removed. The molar ratio of hevein to the C-terminal domain in the lutoid-body fraction of rubber latex is about 30:1. This indicates that not only the pre- and propeptides but also the 14 kDa domain are removed by proteolysis or other processes in the latex vessel after the processing of hevein has taken place.
