Judul: Pemurnian dan pencirian protease dari ekstrak jamur merang
Abstrak: Enzim protease dari jamur merang (Volvariela volvaceae) yang terdapat di Indonesia memiliki aktivitas fibrinolitik. Penelitian ini bertujuan memurnikan dan mencirikan protease dari ekstrak jamur merang. Ekstrak enzim jamur merang dimurnikan dengan presipitasi amonium sulfat kejenuhan 75%, dialisis (cut off 10 KD), dan kromatografi penukar ion DEAE Sepharose. Pemurnian menghasilkan satu fraksi enzim aktif. Aktivitas spesifik fraksi aktif adalah 0.383 U/mg, dengan tingkat kemurnian 2.681 kali dibandingkan dengan ekstrak enzim kasar. Hasil analisis SDS-PAGE memperlihatkan fraksi aktif protease terdiri atas dua pita protein (15.8 dan 12.9 KD). Aktivitas optimum protease dicapai pada suhu 50 oC dan pH 7. Uji zimogram memperlihatkan bahwa protease mampu menghidrolisis substrat kasein dan fibrinogen dengan konsentrasi 0.01% (b/v). Aktiv itas enzim protease menurun dengan penambahan ion Fe3+. Protease ekstrak kasar dihambat spesifik oleh inhibitor fenilmetilsulfonil fluorida dan N-p-tosil-L-lisinklorometil keton sehingga digolongkan ke dalam kelompok protease serin. ABSTRACT SOLIHATI. Purification and Characterization of Protease from Extract of Straw Mushroom. Under the direction of IRMA H SUPARTO and YANTI. An Indonesian straw mushroom believed to have protease which has fibrinolytic activity. Therefore, the purpose of this research was to study the purification and characterization of protease from crude extract of straw mushroom (Volvariela volvaceae). The extracted straw mushroom went through several steps of purification using ammonium sulfate 75% saturation, dialyzed (cut-off 10 KD), and ion-exchange chromatographed using DEAE Sepharose. The result of the study showed one active fraction of enzyme. The spesific activity of this fraction was 0.383 U/mg, compared to the crude extract it has 2.681 fold high er purification. The enzyme revealed two protein bands at active fraction (15.8 and 12.9 KD) by SDS-PAGE. Its optimum activity was achieved at pH 7 and temperature 50 oC. The Protease effectively hydrolyzed casein and fibrinogen at 0.01% concentration by zymogram. The protease enzyme activity decreased by the addition of ion Fe3+ 5 mM. This enzyme was inhibited strongly by phenylmethylsulphonyl fluoride and N-p-tosyl-L-lysinchloromethyl keton. Therefore, this enzyme that was purified from straw mushroom can be classified as serine protease.
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Judul: Penambahan tepung karaginan sebagai pengental dalam pembuatan saos labu kuning (Cucurbita moschata)
Abstrak: Enzim protease dari jamur merang (Volvariela volvaceae) yang terdapat di Indonesia memiliki aktivitas fibrinolitik. Penelitian ini bertujuan memurnikan dan mencirikan protease dari ekstrak jamur merang. Ekstrak enzim jamur merang dimurnikan dengan presipitasi amonium sulfat kejenuhan 75%, dialisis (cut off 10 KD), dan kromatografi penukar ion DEAE Sepharose. Pemurnian menghasilkan satu fraksi enzim aktif. Aktivitas spesifik fraksi aktif adalah 0.383 U/mg, dengan tingkat kemurnian 2.681 kali dibandingkan dengan ekstrak enzim kasar. Hasil analisis SDS-PAGE memperlihatkan fraksi aktif protease terdiri atas dua pita protein (15.8 dan 12.9 KD). Aktivitas optimum protease dicapai pada suhu 50°C dan pH 7. Uji zimogram memperlihatkan bahwa protease mampu menghidrolisis substrat kasein dan fibrinogen dengan konsentrasi 0.01% (b/v). Aktivitas enzim protease menurun dengan penambahan ion Fe". Protease ekstrak kasar dihambat spesifik oleh inhibitor fenilmetilsulfonil fluorida dan N-p-tosil-L-lisinklorometil keton sehingga digolongkan ke dalam kelompok protease serin.
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Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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