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The 60‐kDa precursor to the dithiothreitol‐sensitive tetrameric protease of spinach thylakoids: structural similarities between the protease and polyphenol oxidase
Author(s) -
Kuwabara Tomohiko
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00911-r
Subject(s) - protease , dithiothreitol , spinach , biochemistry , polyphenol oxidase , photosystem ii , polyclonal antibodies , biology , chemistry , microbiology and biotechnology , enzyme , antibody , peroxidase , photosynthesis , immunology
The 60‐kDa precursor to the 39‐kDa dithiothreitolsensitive protease was purified from photosystem II membranes of spinach. When partially purified 60‐kDa protein was stored at 4°C, the protein was degraded to fragments of 39 and 21 kDa. The 39‐kDa fragment was suggested to be identical to the 39‐kDa protease from effects of dithiothreitol on these polypeptides. The N‐terminal amino acid sequences of the 60‐kDa protein and the 39‐kDa protease were the same, APILPDVEK‐, suggesting that the latter was derived from the N‐terminal portion of the former. Immunostaining with polyclonal antibodies against the 60‐kDa protein indicated that the 60‐kDa protein represents the species that occurs in the native thylakoids. These and other structural properties suggest that the protein might be identical to polyphenol oxidase.