Table 1. Influences of mutations on secreted PLA2 (PLA2) activity.
| Name | Mutagenesis sitea | PLA2 activityb(µmol/min/ml) |
| VP1u(pB19-M20) | – | 0.254 |
| Group I (Catalytic network) | ||
| VP1u(Y130A) | T to G at nt 3011 | 0.002 |
| A to C at nt 3012 | ||
| VP1u(G132A) | G to C at nt 3018 | ND |
| VP1u(D154A) | A to C at nt 3084 | ND |
| Group II (Binding calcium ions) | ||
| VP1u(H153A) | C to G at nt 3080 | 0.001 |
| A to G at nt 3081 | ||
| VP1u(Y157F) | A to T at nt 3093 | 0.003 |
| VP1u(Y168F) | A to T at nt 3126 | ND |
| VP1u(D175A) | A to G at nt 3147 | 0.002 |
| VP1u(D195A) | A to C at nt 3207 | 0.28 |
| VP1u(Y157F/Y168F) | A to T at nt 3093 | 0.001 |
| A to T at nt 3126 | ||
| VP1u(Y157F/D175A) | A to T at nt 3093 | 0.002 |
| A to G at nt 3147 | ||
| Group III (Phospholipid environment) | ||
| VP1u(K162R) | A to G at nt 3108 | 0.003 |
| Group IV (No-conserved) | ||
| VP1u(P133R) | C to G at nt 3021 | 0.213 |
| VP1u(A207Y) | G to U at nt 3042 | 0.002 |
| C to A at nt 3043 | ||
| bv PLA2 | – | 0.316 |
| PBS | – | 0 |
ND means non-detected.
a
Nucleotide numbers are based on the sequence of the J35 isolate (GenBank accession no. AY386330).
b
Enzyme activity was measured by a colorimetric assay kit (Cayman Chemical). Protein concentrations tested: recombinant proteins VP1u(WT, P133R, D154A, H153A, Y157F, Y168F, D175A, D195A, Y157F/Y168F, Y157F/D175A, K162R, and A207Y), 5 µg; bee venom, 10 ng.