[Characterization of endogenous phosphorylation substrates of sarcoplasmic reticulum fragments from fast skeletal muscles of the rabbit].
Separation of phosphorylated sarcoplasmic reticulum (SR) fragments by polyacrylamide gel disc electrophoresis in the presence of Na-DS revealed that the radioactivity is distributed in protein zones with molecular weights of 95,000 and 6000-8000. The phosphorylation of the protein with m. w. of 95,000 is Ca2+-dependent. The tryptic hydrolysis of the phosphorylated SR fragments from fast skeletal muscles results in a loss of radioactivity by 60-70%; phospholipase C from Clostridium welchii reduces the labelled phosphate content by 40-50%. The cAMP-dependent protein kinase inhibitor decreases the phosphorylation of both substrates. The substrate of phosphorylation with m. w. of 6000-8000 is not stained with Amidoschwartz 10B or Coumassie brilliant blue. Extraction by an acidified chlorophorm--methanol mixture results in a proteolipid with specific radioactivity exceeding that of the original preparation of phosphorylated SR membranes 3-4-fold. Thin-layer chromatography on Silufol plates and Silicagel KSK showed that the proteolipid is not chromatographically homogeneous after 2-fold precipitation by diethyl ether and is localized in a band with Rf varying from 0.6 to 0.8. The fluorescence spectrum of the proteolipid in a chlorophorm--methanol--HCl solution is represented by an assymmetrical structure-free band with a maximum at 350 nm. A possible role of phosphorylase b and proteolipid in manifestation of the functional activity of the SR fragments is discussed.
D000818:Animals; D008970:Molecular Weight; D009132:Muscles / Q000378:metabolism*; D010446:Peptide Fragments / Q000032:analysis; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D014357:Trypsin; D010738:Type C Phospholipases
D010446:Peptide Fragments; D011506:Proteins; D011494:Protein Kinases; D010738:Type C Phospholipases; D014357:Trypsin
Kharakteristika substratov endogennogo fosforilirovaniia fragmentov sarkoplazmaticheskogo retikuluma bystrykh skeletnykh myshts krolika.