Beschreibung:
<jats:p>A differential analysis of CuZn‐superoxide dismutase (SOD. EC 1.15.1.1) isozymes after native‐polyacry lamide gel elecrrophoresis (PAGE) and isoelectric focusing (IEF) indicated that germinating seeds of Scots pine <jats:italic>(Pinus sylvestris L.)</jats:italic> 3 days after the start of imbibition (3 DAI) contain five CuZn‐SOD isozymes. Two isozymes co‐migrated on native–PAGE but were separated after IEF. CuZn‐SODs of Scots pine were purified from germinating seeds (3 DAI) by anion‐exchange chromatography, hydrophobic interaction chromatography and chromatofocusing. The final separation of CuZn‐SOD isozymes was accomplished by native‐PAGE. CuZn‐SOD isozymes were electroblotted and their NH<jats:sub>2</jats:sub>‐terminal amino acid sequence was determined. Comparisons of the amino acid sequences with sequences of CuZn‐SOD isozymes from other plant sources indicated that one CuZn‐SOD isozyme was of the chloroplastic type whereas the other four isozymes belonged to the cytosolic‐type CuZn‐SODs, The NH<jats:sub>2</jats:sub>‐terminal amino acid sequence of the chloroplastic CuZn‐SOD and of one cytosolic‐type CuZn‐SOD were identical to those of two previously isolated, sequenced and localized CuZn‐SOD isozymes from Scots pine needles. Two cytosolic‐type CuZn‐SOD isozymes showed a homology at 20 out of 21 NH<jats:sub>2</jats:sub>‐terminal amino acids. Mitochondria and glyoxysomes were isolated by differential and Percoll density‐gradient centrifugation from germinating seeds (3 DAI). The cell fractionation experiments did not suggest that a major part of the CuZn‐SOD activity in germinating seeds was derived from glyoxysomes or mitochondria.</jats:p>