Serum Nadp Spesifik İzositrat Dehidrojenaz Enziminin Kinetik Özellikleri

Abstract

Bu çalışmada insan serumu kaynaklı NADP spesifik ICD enziminin katalitik özellikleri araştırıldı. Enzim kaynağı olarak insan serumu kullanıldı. Enzimin isositrat subsratı için Km değeri 159 mikroMol, NADP için 43 ve Mn*t için 194 mikroMol bulundu. Aktivite enzim konsantrasyonunun lineer bir fonksiyonudur. Zaman igin de ilk 60 dakika için lineer bir bağıntı mevcuttur. Enzim 55°C civarinda maksimal aktivite gdstermektedir, Optimum pH 7,5 - 8 arasindadir. Mangan iyonu enzimi maksimum ölçüde aktive etmektedir. Kobalt iyonu manganın 1/3 i ve magnezyum 1/4 i kadar aktive edebilmektedir. Cinko, mangan iyonunun yaptığı aktivasyonu % 83 oraninda inhibe etmektedir. Bakir enzime inhibitSr etki göstermektedir. +4°C de 1 hafta bekletilen serumun orijinal ICD aktivitesi % 20 oraninda azalmaktadir.

Keywords

• SERUM NADP SPESİFİK İZOSİTRAT DEHİDROJENAZ ENZİMİNİN KİNETİK ÖZELLİKLERİ
• serum
• enzim

KINETIC PROPERTIES OF SERUM NADP SPECIFIC ISOCITRATE DEHYDROGENASE ENZYME

Abstract

In this study, the catalytical activity properties of human serum NADP-linked isocitrate dehydrogenase were investigated according to the enzyme kinetics parameters. Km values of serum NADP linked ICD for isocitrate, NADP* and manganese substrates were found as 159, 43 and 194 microMoles respectively. The correlation between the enzyme activity and the enzyme concentration was found as linear. For the first 60 minutes of the reaction, the correlation between time and the enzyme activity can be considered as lincar. The activity was greatest near 55°C. Above this temperature the activity fell down rapidly. Optimum pH was between 7,5 - 8,0. The enzyme needed the presence of metal ions for its activity. Manganese activated the enzyme maximally. Cobalt and magnesium ions activated the enzyme only 1/3 and 1/4 of that of manganese activation, Zinc inhibited the manganese activation by 83 percent and copper by 87 percent. Activity was negligible when there was no metal ions in the medium. Serum which was priserved at 4°C for one week lost 20 precent of its original activity.

Keywords

• KINETIC PROPERTIES OF SERUM NADP SPECIFIC ISOCITRATE DEHYDROGENASE ENZYME
• serum
• enzyme

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