The time course of growth, biosynthesis and secretion of different phosphoh
ydrolytic activities by Nicotiana tabacum 1507 cell suspension culture were
investigated. It was established that the cell culture under study biosynt
hesised large amounts of phosphohydrolytic activities during the linear pha
se of growth for a relatively short period (between the 2nd and 5th days of
cultivation). The highest enzyme activity was determined with bis-pNPP whi
ch is non-specific substrate for phosphodiesterases and for some nucleases
(116.10(3) U/L at pH 5.7 and 51.10(3) U/L at pH 8.0). The different phospho
hydrolytic activities were distingnished using specific substrates at pH 5.
7 (20.10(3) U/L - 5'-phosphodiesterases, 18,8.10(3) U/L - 3'-phosphodiester
ases and 15,5.10(3) U/L - phosphomonoesterases) and at pH 8.0 (10,2.10(3) U
/L - 5'-phosphodiesterases, 9,5.10(3) U/L - 3'-phosphodiesterases and 6,4.1
0(3) U/L - phosphomonoesterases).