title: AMP and IMP dissociate actomyosin into actin and myosin.
abstract: We investigated to determine why heating of squid muscle at 60 degrees C induced the liberation of actin from myofibrils. When a mixture of a myofibrillar fraction and a low-molecular sarcoplasmic fraction prepared from squid muscle was heated at 60 degrees C, actin liberation occurred. When a myofibrillar fraction was heated with ATP, AMP, or IMP, actin liberation occurred. Hence, AMP is perhaps one of the factors causing actin liberation in postmortem squid muscle. It was found that AMP and IMP reversibly dissociated actomyosin of chicken, bovine, and porcine skeletal muscles into actin and myosin on incubation at 0 degrees C at pH 7.2 in 0.2 M KCl. These results led us to conclude that AMP and IMP were the most responsible factors causing actin liberation from myofibrils in the heated muscle and causing reversible dissociation of actomyosin on storage of skeletal muscle at a low temperature. Hence, AMP and IMP are possible factors causing the resolution of rigor mortis in muscles.
authors.affiliation: Department of Food Science and Technology, Nippon Veterinary and Life Science University, Musashino-shi, Tokyo, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Okitani
authors.forename: Naoki
authors.initials: N
authors.lastname: Ichinose
authors.forename: Miki
authors.initials: M
authors.lastname: Koza
authors.forename: Kensuke
authors.initials: K
authors.lastname: Yamanaka
authors.forename: Koshiro
authors.initials: K
authors.lastname: Migita
authors.forename: Masanori
authors.initials: M
authors.lastname: Matsuishi
mesh_terms: D000199:Actins / Q000378:metabolism*; D000205:Actomyosin / Q000378:metabolism*; D000249:Adenosine Monophosphate / Q000378:metabolism*; D000818:Animals; D049832:Decapodiformes / Q000378:metabolism; D006358:Hot Temperature; D007291:Inosine Monophosphate / Q000378:metabolism*; D008970:Molecular Weight; D009218:Myosins / Q000378:metabolism*
chemical_list: D000199:Actins; D007291:Inosine Monophosphate; D000249:Adenosine Monophosphate; D000205:Actomyosin; D009218:Myosins