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. | Tr. J. of Biology 22 (1998) 211-216 © TÜBİTAK Determination of 5’-Nucleotidase Activity of Higher Plants by Using an Improved Method* Yusuf TURAN Balıkesir University, Faculty of Education, Biology Department, Balıkesir-TURKEY Received: Abstract: 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 NaMoO4 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. Key Words: 5’-Nucleotidase, nucleoside 5’-monophosphate, phosphatase, specific activity, pyrimidine. Yüksek Bitkilerde 5’-Nükleotidaz Aktivitesinin Geliştirilmiş Bir Yöntemle Tayini Özet: Çeşitli bitki dokularında nispeten yüksek, spesifik olmayan fosfataz aktivitelerinin varlığı bilinmektedir. Bu enzimler aynı zamanda nükleosit monofosfatlardan da inorganik fosfatın uzaklaştırılmasını katalize ederler. Şimdiye kadar yayınlanan raporlara göre, saflaştırılmamış enzim ekstraktlarında 5’-nükleotidaz aktivitesiyle ilgili deneysel araştırmalar çoğunlukla spesifik olmayan fosfatazların aktiviteleri dikkate alınmadan yapılmıştır. Bununla birlikte bazı araştırıcılar, fosfatazların NaMoO4 ve KF gibi bazı inhibitörlerini assay karışımlarına ilave etmişlerdir. Fakat fosfatazlar bu inhibitörlerle tamamen inhibe .
