As one of the five Granzymes (A, B, H, K and M) identified
in the human genome, Granzyme B
(32kDa) (5) is the most widely researched in terms of its
biological function and its utility in
health and disease (4). It is synthesized as a precursor
(247 residues) with a signal peptide
(residues 1-18), a pro-peptide (residues 19-20), and a
mature chain (residues 21-247) (6-8).
Once inside granules, Granzyme B is fully processed into the
mature chain and becomes an
active protease when the pro-peptide, Gly-Glu is removed
from the N-terminus by cleavage
with Cathepsin C (9). The protease activity of Granzyme B is
tightly controlled by Serpin B9/
Protease Inhibitor 9 (9). The amino acid sequence of human
Granzyme B is 71%, 69%, and 68%
identical to its canine, rat, and mouse counterparts,
respectively.
Granzymes have been shown to modulate inflammation, and
Granzyme B plasma levels have
been found higher with atopic dermatitis and psoriasis when
compared to healthy controls.
This is in contrast to Granzyme A plasma levels which remain
unchanged (10). Serum from
patients with Crohn's disease have significantly higher
Granzyme B levels than controls (11).
