Accession Number : ADA185694

Title :   Entropic Elastic Processes in Protein Mechanisms. Part 2. Simple (Passive) and Coupled (Active) Development of Elastic Forces,

Corporate Author : ALABAMA UNIV IN BIRMINGHAM LAB OF MOLECULAR BIOPHYSICS

Personal Author(s) : Urry, Dan W

PDF Url : ADA185694

Report Date : Jan 1986

Pagination or Media Count : 65

Abstract : It was demonstrated that elastic structure develops as the result of an inverse temperature transition and that entropic elasticity is due to internal chain dynamics in a regular non-random structure. This demonstration is contrary to the pervasive perspective of entropic protein elasticity of the past three decades wherein a network of random chains has been considered to be the necessary structural consequence of the occurrence of dominantly entropic elastomeric force. Entropic elastic processes are considered in two classes: passive and active. The development of elastomeric force on deformation is Class I (passive) and the development of elastomeric force as the result of a chemical process shifting the temperature of a transition in Class II (active). Examples of Class I are elastin, the elastic filament of muscle, elastic force changes in enzyme catalysis resulting from binding processes and resulting in the straining of a scissile bond, and in the turning on and off of channels due to changes in transmembrane potential. Demonstration of the consequences of elastomeric force developing as the result of an inverse temperature transition are seen in elastin where elastic recoil is lost on oxidation, i.e., on decreasing the hydrophobicity of the chain and shifting the temperature for the development of elastomeric force to temperatures greater than physiological. This is relevant in general to loss of elasticity on aging and more specifically to the development of pulmonary emphysema.

Descriptors :   *ELASTIC PROPERTIES, *PASSIVE SYSTEMS, *PROTEINS, *ENTROPY, CATALYSIS, CHEMICAL REACTIONS, DEFORMATION, DYNAMICS, EMPHYSEMA, ENZYMES, FILAMENTS, HYDROPHOBIC PROPERTIES, INVERSION, LUNG, MUSCLES, OXIDATION, RECOIL, TEMPERATURE, TRANSITIONS, MOLECULE MOLECULE INTERACTIONS, CHEMICAL BONDS

Subject Categories : Biochemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE