Determination of the native subunit pattern of gizzard tropomyosin using antibodies specific to each subunit.
The gizzard tropomyosin molecule is composed of two subunits at 1:1 molar ratio. Possible composites of the tropomyosin molecule are two kinds of homodimer (one for each subunit), a heterodimer of two subunits, or a mixture of heterodimer and homodimer(s). We tried to evaluate the native subunit composition of gizzard tropomyosin by cross-linking experiments and immunological methods using specific antibodies to each subunit. For the cross-linking experiment we used dimethyl suberimidate, an amino group-specific cross-linker, in the presence of dithiothreitol to avoid artificial oxidative intersubunit cross-linking. When gizzard tropomyosin was cross-linked, it generated several products which might correspond to dimers formed by intersubunit cross-linkage. When the reaction was carried out for a long time, non-cross-linked subunits completely disappeared and two or three major cross-linked products arose. All of these cross-linked products were recognized by both of the specific antibodies to each subunit. These results indicated that the predominant part, if not all, of gizzard tropomyosin is present as heterodimer.
Nakamura
S
S
Department of Pharmacology, Faculty of Medicine, University of Tokyo.
Sakurai
T
T
Nonomura
Y
Y
D000818:Animals; D000918:Antibody Specificity; D002645:Chickens; D003432:Cross-Linking Reagents; D004120:Dimethyl Suberimidate; D005895:Gizzard, Avian / Q000737:chemistry; D008970:Molecular Weight; D011487:Protein Conformation; D014335:Tropomyosin / Q000737:chemistry* / Q000276:immunology
D003432:Cross-Linking Reagents; D014335:Tropomyosin; D004120:Dimethyl Suberimidate