Studies of a key protein in the mechanism of the excitation-contraction coupling process of frog skeletal muscle, using phenylglyoxal.
The excitation-contraction (E-C) coupling process in single twitch fibres from frog toe muscle was inhibited selectively by phenylglyoxal (PGO), a specific guanidyl modifying reagent. A new protein (31.5 kDa), which has PGO-binding ability and seems to play a key role in the E-C coupling process, was solubilized from transverse tubule membrane-junctional sarcoplasmic reticulum complexes (TTM-JSR) of frog skeletal muscles, using 14C-PGO. The monoclonal antibody against this protein applied extracellularly inhibited the E-C coupling process of the single fibres. This protein appears to constitute the very first step of input for E-C coupling. It is considered to behave as an indispensable part of an 'electrometer' to measure membrane potentials. Therefore, the name 'electrometrin' is suggested for the new protein.
Fujino
S
S
Department of Pharmacology, Hokkaido Institute of Pharmaceutical Sciences, Otaru, Japan.
Satoh
K
K
Nakai
T
T
Togashi
K
K
Kado
T
T
Fujino
M
M
Arima
T
T
Fujino
M
M
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D004594:Electrophysiology; D066298:In Vitro Techniques; D008970:Molecular Weight; D009119:Muscle Contraction / Q000187:drug effects*; D009124:Muscle Proteins / Q000302:isolation & purification / Q000502:physiology*; D009132:Muscles / Q000502:physiology*; D010658:Phenylglyoxal / Q000494:pharmacology*; D011898:Ranidae; D012995:Solubility
D000911:Antibodies, Monoclonal; D009124:Muscle Proteins; D010658:Phenylglyoxal