Determination of 5' nucleotidase activity of higher plants by using an improved method

Çesitli bitki dokularında nispeten yüksek, spesifik olmayan fosfataz aktivitelerinin varlıgı bilinmektedir. Bu enzimler aynı zamanda nükleosit monofosfatlardan da inorganik fosfatın uzaklastırılmasını katalize ederler. Simdiye kadar yayınlanan raporlara göre, saflastırılmamıs enzim ekstraktlarında 5’-nükleotidaz aktivitesiyle ilgili deneysel arastırmalar çogunlukla spesifik olmayan fosfatazların aktiviteleri dikkate alınmadan yapılmıstır. Bununla birlikte bazı arastırıcılar, fosfatazların $NaMoO_4$ ve KF gibi bazı inhibitörlerini assay karısımlarına ilave etmislerdir. Fakat fosfatazlar bu inhibitörlerle tamamen inhibe edilmeden 5’-nükleotidazın aktivitesine katılmıslardır. Bu yüzden mevcut çalısmada, saflastırılmamıs enzim ekstraktlarında spesifik olmayan fosfataz aktiviteleri, substrat olarak p-nitrofenil fosfatın kullanılmasıyla tayin edilmis ve dolayısıyla 5’-nükleotidaz aktivitesi de, ilk defa, fosfatazların aktivitesinin de dikkate alınmasıyla dogru olarak belirlenmistir

Yüksek bitkilerde 5' nükleotidaz aktivitesinin geliştirilmiş bir yöntemle tayini

The presence of relatively high non-specific phosphatase activities are known in various plant tissues. These enzymes also catalyze the removal of inorganic phosphate from nucleoside monophosphates. According to published reports, so far, the experimental investigations, concerning the 5’-nucleotidase activity, have been mostly carried out without consideration of the non-specific phosphatase activities in crude enzymic extracts. However, few researchers have been included some inhibitors of these phosphatases, such as $NaMoO_4$ or KF, in assay mixtures. But phosphatases are not completely inhibited by these inhibitors and, therefore, interfere the activity of 5’-nucleotidase. Thus, the non-specific phosphatase activities were determined in crude enzymic extracts by using p-nitrophenyl phosphate as substrate and the apparent 5’-nucleotidase activity was, first time, corrected accordingly in this present work.

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