Drosophila melanogaster로부터 새로운 단백질 분해 효소를 순수 정제하였다. 이 효소의 분자량은 150,000Da이고 소단위 분자량은 38,000Da이었고, 아미노 말단 부위의 서열과 아미노산 조성은 알려진 다른 단백질 분해 효소들과는 다른 특정을 보였다. 효소 활성의 적정 pH와 온도는 각각 pH 9-10, $42^{circ}C$였다. 기질에 대해서는 trypsin과 같은 특이성을 보였으며, 주변 아미노산들의 영향을 많이 받았다. 이 효소는 대부분의 serine proteinase 저해물질과 몇몇 cysteine proteinase 저해 물질에 의해 저해 받았지만, PMSF와 E64는 효소활성에 영향을 주지 않았다. 반응시킨 여러 물질들 가운데 poly-L-lysine은 효소활성을 증진시킨 반면에 ATP는 효소 활성을 억제하는 것으로 나타났다. 이 효소는 성장과정에서 엄격하게 발현이 조절됨을 Western 분석결과로부터 알 수 있었다.
A new proteinase has been purified to apparent homogeneity from Drosophila melanogaster. The molecular weight of the native enzyme was estimated to be 150,000. In the presence of SDS, the enzyme can be dissociated into seemingly identical subunits of 38,000 molecular weight. The $NH_2$-terminal sequence of the enzyme and the amino acid composition data showed marked difference from those of known proteinases. The pH and temperature optima for the activity were pH 9.0-10 and $42^{circ}C$, respectively. The enzyme exhibited trypsin-like specificity, but the activity was also affected by the neighboring amino acids. The enzyme was inhibited by most of the serine proteinase inhibitors and some of the agents that inhibit cysteine proteinases, however, PMSF and E64 showed no effect on the activity of the enzyme. Among the other compounds tested, the activity was stimulated by poly-L-lysine, whereas ATP caused a decrease in the activity of the purified enzyme. A polyclonal antiserum generated against the purified enzyme was used to analyse the proteinase and the result suggested that the production of the proteinase is controlled rather strictly during development.
