TABLE 2

Clusters not matching venom components that may be associated with venom functions

ProductNo. of ESTsReason
5′ nucleotidase35′ nucleotide degradation activity is widely described in snake venoms but the enzyme responsible for it has never been characterized. The molecule found has a signal peptide.
ADAM (a disintegrin and metalloprotease)1Metalloproteases closely related to the SVMPs, the important toxins from Viperidae. The sequence found showed a strong match to ADAM 4 at the C-terminal spacer portion.
Cathepsins L and S2Although cysteine proteases have never been described in snake venoms, they could be involved in venom processing. Due to the importance of proteases in envenoming, they may also be involved in toxicity.
uPAR (urokinase type plasminogen activator receptor)1Tissue-type plasminogen activator is present in most Viperidae venoms. This uPAR may point to some involvement of uPAR in coagulation disturbances. Its second 3FTx domain is aligned in Figure 6.
S-lectin1Galectins show cell-surface interaction functions that may be related to the roles of CTL. These proteins are secreted without a signal sequence and were never described in snake venoms.
β-PLIs (β-PLA2 inhibitors)10β-PLIs are trimeric proteins of 50-kDa glycosylated subunits, known for inhibiting venom PLA2s. They were isolated from plasma of only two snake species and thought to be expressed in the liver and then secreted.
TIMP (tissue inhibitors of metalloproteases)2May be an inhibitor of SVMPs. TIMP1 has never been described as a natural protective molecule against SVMPs, although several other types of inhibitors were described in snake sera.