Rabbit fast skeletal muscle phospholipase C Molecular weight determination by renaturation after polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate

FEBS Letters ◽  
1992 ◽  
Vol 313 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Volker Windhofer ◽  
Magdolna Varsànyi ◽  
Ludwig M.G. Heilmeyer
1979 ◽  
Vol 183 (2) ◽  
pp. 339-347 ◽  
Author(s):  
Jean-Louis Azanza ◽  
Jacques Raymond ◽  
Jean-Michel Robin ◽  
Patrick Cottin ◽  
André Ducastaing

Ca2+-activated neutral proteinase was purified from rabbit skeletal muscle by a method involving DEAE-Sephacel chromatography, affinity chromatography on organomercurial–Sepharose and gel filtration on Sephacryl S-200 and Sephadex G-150. The SDS (sodium dodecyl sulphate)/polyacrylamide-gel-electrophoresis data show that the purified enzyme contains only one polypeptide chain of mol.wt. 73000. The purification procedure used allowed us to eliminate a contaminant containing two components of mol.wt. about 30000 each. Whole casein or α1-casein were hydrolysed with a maximum rate at 30°C, pH7.5, and with 5mm-CaCl2, but myofibrils were found to be a very susceptible substrate for this proteinase. This activity is associated with the destruction of the Z-discs, which is caused by the solubilization of the Z-line proteins. The activity of the proteinase in vitro is not limited to the removal of Z-line. SDS/polyacrylamide-gel electrophoresis on larger plates showed the ability of the proteinase to degrade myofibrils more extensively than previously supposed. This proteolysis resulted in the production of a 30000-dalton component as well as in various other higher- and lower-molecular-weight peptide fragments. Troponin T, troponin I, α-tropomyosin, some high-molecular-weight proteins (M protein, heavy chain of myosin) and three unidentified proteins are degraded. Thus the number of proteinase-sensitive regions in the myofibrils is greater than as previously reported by Dayton, Goll, Zeece, Robson & Reville [(1976) Biochemistry15, 2150–2158]. The Ca2+-activated neutral proteinase is not a chymotrypsin- or trypsin-like enzyme, but it reacted with all the classic thiol-proteinase inhibitors for cathepsin B, papain, bromelain and ficin. Thus the proteinase was proved to have an essential thiol group. Antipain and leupeptin are also inhibitors of the Ca2+-activated neutral proteinase.


1985 ◽  
Vol 38 (3) ◽  
pp. 327 ◽  
Author(s):  
H WG Baker ◽  
LW Eddie ◽  
B Hudson ◽  
HD Niall

An in vitro bioassay based on suppression of GnRH-stimulated FSH secretion by pituitary cells in culture was used to monitor inhibin activity after dialysis, gel filtration or polyacrylamide gel electrophoresis of protein preparations from a variety of gonadal secretions and extracts under native and dissociating conditions. The suggestion that inhibin is a peptide of molecular weight less than 5000 was not confirmed. Although some fractions of low molecular weight suppressed FSH secretion, the amount of activity was low and the dose response curves were not parallel with a standard preparation of inhibin. Under most conditions, inhibin eluted with an apparent molecular weight of about 90 000. However, gel filtration of rete testis fluid protein in I M acetic acid resulted in elution of inhibin activity with a lower apparent molecular weight and with polyacrylamide gel electrophoresis in o� 1% (w/v) sodium dodecylsulfate, the apparent molecular weight was 30 000. It is concluded that inhibin is a protein which tends to aggregate and coelute with larger molecules.


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