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Major (Al, Fe), minor (Mn), and trace (Li, Cu, Ni, Cr, Cd, Zn, Pb) metals along with nutrients (TOC, TON, TS, TP) and enzymatic activities were determined in 18 surface sediment and two soil samples collected in six small bays of the Karelian shore of Kandalaksha Bay, White Sea, Russian Arctic. The studied sediments tended to be marine, with a major input of organic matter from autochthonous sources. Marine organic material might be an important carrier of trace metals in the examined sediments. According to sediment quality guidelines, all tracemetal contents were below the threshold levels. The results of azocasein-trypsin tests also suggested no significant contamination of analysed sediments and soils. A comparison of the trace-metal contents in the sediments examined with those of the western Arctic shelf showed higher levels of Zn and Cr in the Karelian shore. Presumably these disparities were related to regional differences in sediment chemistries rather than to any enhanced pollution within the studied area. Both geochemical composition and enzymatic-activities patterns among sites studied are largely controlled by the sediment granulometry. The evolution of sediments in the restricted exchange environments under investigation is caused by depositional conditions, which are strongly affected by small-scale hydrodynamic processes specific for each particular area. The most vivid examples are separating basins, where the fine-grained sediments enriched in organic matter -and thus in nutrients and metals -are formed under calm hydrodynamic conditions enhanced by severely restricted water exchange.

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The primary structure of the nucleic acid from the branching enzyme 1,4-1x-~-glucan : 1,4-a-Dglucan 6-a-( 1,4-a-gIucano)-transferase (2.5-S RNA) isolated from rabbit muscles has been elucidated. The polyribonucleotide consists of 31 nucleotides; the unique features of the polyribonucleotide are the unusually high content of modified nucleotides (32 %) and guanine residues (40 %). Apparently 2.5-S RNA belongs to a class of nucleic acids unknown up to now.It is the first time that the structure of a nucleic acid component from a ribonucleoenzyme has been defined. This work is a prerequisite for gaining insight into the intimate activating effect of the polyribonucleotide on the enzyme action.

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