Using a standard protein marker, the two narrow bands at 8 and 16.5 ml of elution volume were found to be 200 and
23 kDa, respectively. The broad band corresponded to 174–37 kDa.This result shows consistency with previous SDS-PAGE results that the molecular weight of hot-water extracted SS lies between 17 and 250 kDa [17–19]. It also supports that the hot-water extracted SS is highly degraded compared to original sericin in the silkworm gland [16,17].