| Silicatein-like proteins that catalyze the condensation of organic silica were isolated from 3 species of marine sponges (Codename: minsel-3, minsel-4, and Axi). Two of the samples, minsel-3 and minsel-4 were originated from Bunaken marine conservation and another sample, Axi was originated from coast of Jakarta. The protein was isolated from marine sponges by stripped the spicules off from its coat of silica polymers with hydrofluoric acid (HF, 5%) and ammonium fluoride buffer (HF, 2M/ NH4F, 8M). Results of SDS-PAGE showed that the molecular weights of the proteins are ±26.6kDa & ±84.0kDa for minsel-3, ±16.5kDa & ±37.6kDa for minsel-4, and ±18.1kDa for Axi. The dialysed proteins were then characterized and assayed to determine its activity. The proteins were reacted with TEOS at neutral pH and room temperature for 24 hours. Results from activity assay of the proteins after reacted with TEOS produced accumulation of tetrahydroxysilane at 181.71?mol/ml for minsel-3, 884.12?mol/ml for minsel-4, and 104.35?mol/ml for Axi. On the second experiment, interfering substances were introduced by pre-incubating the isolated protein specifically from sample Axi with 5% glycerol and 1% D-glucose for 1 hour and continued with incubating with TEOS substrate. The result of standard reaction between the isolated proteins with TEOS substrate produced accumulation of 1452.35?mol/ml of TEOS monomer. The results between pre-incubated protein in 5% glycerol and 1% D-glucose produced accumulation of 295.29?mol/ml and 333.92?mol/ml of TEOS monomer respectively. These results were much more lowly compared to the standard reaction. Hence, it can be assumed that the presence of substances, glycerol and glucose somehow interfered and affect the polymerization of silica to the protein. |