Open AccessPhysicochemical Characterization and Specificity of the Murine Leukaemia Virus Pr65gag Proteolytic Factor
Author(s) -
Yoshiyuki Yoshinaka,
Ronald B. Luftig
Publication year - 1980
Publication title -
journal of general virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.55
H-Index - 167
eISSN - 1465-2099
pISSN - 0022-1317
DOI - 10.1099/0022-1317-48-2-329
Subject(s) - cleavage (geology) , sephadex , protease , in vitro , biology , virus , in vivo , microbiology and biotechnology , proteolysis , factor ix , peptide , virology , biochemistry , enzyme , genetics , paleontology , fracture (geology)
The Pr65gag proteolytic factor obtained from Moloney (MoLV) or Rauscher (RLV) leukaemia virus has been characterized. We found that it was present in small amounts in virions and was extremely unstable. Although it eluted at the trailing edge of p12 on Sephadex G-75 columns, it could clearly be separated from p12 on DEAE-Sephadex A-50M columns, making it unlikely that the factor is p12 or any other major murine leukaemia virus (MuLV) protein. This fact also distinguishes the murine factor from the avian tumour viruses and is stable to column purification methods (von der Helm, 1977; Dittmar & Moelling, 1978). We further observed that: (i) the murine proteolytic factor had an estimated mol. wt. of 20,000 to 22,000, relative to MuLV p12, which eluted as a dimer on Sephadex G-75 columns in the presence of 0.1% NP-40; and (ii) in vitro cleavage of an iodinated Pr65gag-rich, p30-deficient substrate yielded a clear increase in both p30 and p12, which suggests that the in vitro cleavage of Pr65gag is similar to its processing in vivo.