Preliminary Study On The Extracellular Enzymatic Activity And The Affecting Factors In The Jiaozhou Bay

Spatial distribution and seasonal variation of activities of extracellular enzymes of alkaline phosphatase, peptidase, aminoglucosidase in the Jiaozhou Bay were investigated through the fluorogenic-model-substrate approach during 2000?001. Particularly, intensive time series (sampling at every other week) investigation of activities of the above three enzymes and the saturated activity of alkaline phosphatase were conducted at one of the 6 stations, St.7, for a period of one year from May 2000 through June 2001. In addition, the effect of Zn2~, Cu2~ and temperature on the activity of these enzymes were also tested using surface water from St.7 and another site near the Navigation School harbor on the east coast of the bay. Following are the main results. 1 Among the three enzymes, peptidase ranked the No.1 in terms of activity, followed by alkaline phosphatase, and aminoglucosidase came the last. 2 Annual variation patterns of activities of alkaline phosphatase, peptidase and aminoglucosidase as well as the saturated activity of alkaline phosphatase were quite similar to that of ambient water temperature. 3 In situ experiments indicated that Zn2+ has dual nature on alkaline phosphatase activity, either as a promoter or an inhibitor depending on its ambient concentration. 2+ Cu was shown to be simply an inhibitor of extracellular enzymatic activity within the range applied in the present study. Its negative effects can be an order of magnitude greater than that of Zn2+. 4 By increasing ambient temperature, extracellular enzymatic activities were 1~ enhanced to certain extent (up to l60~445%), but temPeratUre above 35 'Crestrained the activities of peptidase probably due to protein denAnlization.