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Identification of a 68 kDa protein which copurifies with type‐1 protein phosphatase as albumin
Author(s) -
Villa-Moruzzi Emma,
Meyer Helmut E.,
Heilmeyer Ludwig M.G.
Publication year - 1986
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(86)80647-0
Subject(s) - phosphatase , biochemistry , albumin , size exclusion chromatography , chemistry , microbiology and biotechnology , glycogen phosphorylase , protein phosphatase 1 , gel electrophoresis , protein a/g , chromatography , biology , glycogen , enzyme , fusion protein , recombinant dna , gene
Proteins of 60–70 kDa copurify with some preparations of type‐1 or type‐2 phosphatases. In our system chromatography on polylysine‐Affi‐Gel 10 separates a 68 kDa protein from rabbit muscle glycogen particle phosphorylase phosphatase. The separation affects neither the activity nor the size of the phosphatase. The 68 kDa protein, although pure by SDS gel electrophoresis criteria, still displays phosphatase activity of approx. 6–8 . However, rechromatography either on Bio‐Gel A‐0.5 m or on Blue Sepharose CL‐6B followed by gel filtration shows that the activity is due to a contamination with phosphatases of type 1 and type 2, displaying a molecular mass of 35 kDa, which can be totally removed from the 68 kDa protein. The amino acid composition of the 68 kDa protein is identical to that of rabbit serum albumin, within the limits of variation of the method. Furthermore, the sequence of the 38 N‐terminal amino acids is the same in the isolated 68 kDa protein and in rabbit serum albumin.