C31S BS-RNase or C32S BS-RNase |
Sulfhydryl group carboxymethylation |
Not quantitated |
Reduced affinity for RI |
Specifically toxic to spermatogenic layers |
200 |
RNase A |
Carboxyl group amidation with ethylenediamine |
1.6% of RNase A |
Ribonucleolytic activity reduced by 10-fold molar excess of RI |
0.17 μM (3T3-SV40) |
18 |
RNase 1 |
Carboxyl group amidation with ethylenediamine |
0.38% of RNase A |
Ribonucleolytic activity reduced by 10-fold molar excess of RI |
0.13 μM for (3T3-SV40) |
18 |
RNase A |
Carboxyl group amidation with ethylenediamine to Z = +15.6 |
5% of RNase A |
19 nM |
0.085 μM (MCF-7) 0.075 μM (3T3-SV40) |
48 |
RNase A |
Carboxyl group amidation with polyethylenimine (250, 600, 1000, 1800 Da) |
Not determined |
“Markedly decreased” affinity for RI” |
0.33–3.3 μM (3T3-SV40) |
201 |
RNase A |
Amino group amidation with PEG (5, 22 kDa) |
Not determined |
Not determined |
Aspermatogenic and anti-tumoral activity |
168 |
RNase A |
Amino group amidation with PHPMA (classic and star-like) |
Not determined |
Not determined |
Tumor growth inhibited in CD-1 nude mice bearing human tumors |
170 |