Biomaterial Database

Modification of K channel inactivation by papain and N-bromoacetamide. 1988

D R Matteson, and P Carmeliet

University of Maryland School of Medicine, Department of Biophysics, Baltimore 21201.

The whole-cell variation of the patch clamp technique was used to study macroscopic K current in voltage clamped GH3 cells. An inactivating, voltage-dependent K current was studied in isolation by inhibiting Ca-activated K currents with internal Ca chelators and external tetraethylammonium ions. Under control conditions, the K current inactivated in two phases with time constants of 25 and 79 ms. After treatment with either a proteolytic enzyme such as papain or the amino acid reagent N-bromoacetamide, the K current no longer inactivated rapidly, but decayed very slowly with a time constant of 500 to 750 ms. The action of papain or N-bromoacetamide on K channels is comparable to their action on Na channels, suggesting that inactivation in Na and K channels occurs by a similar mechanism.

UI	MeSH Term	Description	Entries
D007473	Ion Channels	Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.	Membrane Channels,Ion Channel,Ionic Channel,Ionic Channels,Membrane Channel,Channel, Ion,Channel, Ionic,Channel, Membrane,Channels, Ion,Channels, Ionic,Channels, Membrane
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D010206	Papain	A proteolytic enzyme obtained from Carica papaya. It is also the name used for a purified mixture of papain and CHYMOPAPAIN that is used as a topical enzymatic debriding agent. EC 3.4.22.2.	Tromasin
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D004553	Electric Conductivity	The ability of a substrate to allow the passage of ELECTRONS.	Electrical Conductivity,Conductivity, Electric,Conductivity, Electrical
D000081	Acetamides	Derivatives of acetamide that are used as solvents, as mild irritants, and in organic synthesis.
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia