TY - JOUR
T1 - Urea extraction of Z bands, intercalated disks, and desmosomes
AU - Rash, John E.
AU - Shay, Jerry W.
AU - Biesele, John J.
N1 - Funding Information:
The effects of urea on the configurational states of various isolated muscle proteins have been extensively investigated in the last 35 years (19, 23, 31, 38, 39, 42, 43, 44), and the mechanism of denaturation is now sufficiently understood to permit qualitative investigations of whole muscle. Numerous investigators have analyzed the physiological changes in muscle activity after exposure to various concentrations of urea (23, 31), noting especially the effects on myosin (23, 39, 42, 43) and actin (38, 42). In addition, the effects of urea on partially purified tropomyosin have been reported (1, 19, 40, 44), but in none of these reports has electron microscopic examination of the tissue been presented. We have therefore initiated a systematic electron microscopic and electrophoretic study of chick cardiac and striated muscle after varying periods of exposure to urea concentrations from 0.1 M to 8 M. Particular emphasis was placed on attempts to extract relatively pure tropomyosin without excessive actin or myosin contamination. We have thus been able to determine (a) the optimum concentration for the specific extraction of the Z bands, (b) the probable composition of the Z bands, and (c) the probable similarity in composition of the Z band protein to the densely staining material of the intercalated disks and desmosomes. In addi- 1 This research was supported in part by U. S. Public Health Service research grant number GM-15875-04 from the National Institute of General Medical Sciences, training grant number 5 T01 GM-00337 from the National Institute of General Medical Sciences, and research career award number 5-K6-CA-18366 from the National Cancer Institute.
PY - 1968/8
Y1 - 1968/8
N2 - Specific extraction of Z bands, intercalated disks and desmosomes was accomplished with molar concentrations of urea. Thick and thin filaments and M line material were undisturbed, demonstrating that the Z band protein is not similar to actin, myosin, or the M-line protein. The literature indicates that the tropomyosins are the only other structural proteins present in sufficient amounts to account for the extracted Z bands. However, the evidence for a lipid-protein association in the Z bands is considered and is further supported by the close association of the dense material of the Z bands, intercalated disks, and desmosomes with the lipoprotein cell membranes.
AB - Specific extraction of Z bands, intercalated disks and desmosomes was accomplished with molar concentrations of urea. Thick and thin filaments and M line material were undisturbed, demonstrating that the Z band protein is not similar to actin, myosin, or the M-line protein. The literature indicates that the tropomyosins are the only other structural proteins present in sufficient amounts to account for the extracted Z bands. However, the evidence for a lipid-protein association in the Z bands is considered and is further supported by the close association of the dense material of the Z bands, intercalated disks, and desmosomes with the lipoprotein cell membranes.
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U2 - 10.1016/S0022-5320(68)90057-9
DO - 10.1016/S0022-5320(68)90057-9
M3 - Article
C2 - 4883856
AN - SCOPUS:0014317442
SN - 0022-5320
VL - 24
SP - 181
EP - 189
JO - Journal of Ultrasructure Research
JF - Journal of Ultrasructure Research
IS - 3-4
ER -