Biomaterial Database

Freeze-thaw studies of a model protein, lactate dehydrogenase, in the presence of cryoprotectants. 1993

S Nema, and K E Avis

Department of Pharmaceutics, University of Tennessee, Memphis.

The objective of this study was to investigate the behavior of lactate dehydrogenase (LDH) upon freezing and thawing, alone or in the presence of several selected cryoprotectants. Also, the influence of the freezing rate on retainment of LDH activity was investigated. It was observed that fast freezing caused less loss of LDH activity than slow freezing. The probable mechanisms of loss of activity after freeze-thaw cycles were discussed. Selected cryoprotectants were evaluated for their ability to protect LDH during freeze-thaw cycles. Surface tension and pH change measurements upon freezing of the cryoprotectant solutions were carried out. Based on the results of these experiments, a potential mechanism of cryoprotection has been developed.

UI	MeSH Term	Description	Entries
D007770	L-Lactate Dehydrogenase	A tetrameric enzyme that, along with the coenzyme NAD+, catalyzes the interconversion of LACTATE and PYRUVATE. In vertebrates, genes for three different subunits (LDH-A, LDH-B and LDH-C) exist.	Lactate Dehydrogenase,Dehydrogenase, L-Lactate,Dehydrogenase, Lactate,L Lactate Dehydrogenase
D003451	Cryoprotective Agents	Substances that provide protection against the harmful effects of freezing temperatures.	Cryoprotective Agent,Cryoprotective Effect,Cryoprotective Effects,Agent, Cryoprotective,Agents, Cryoprotective,Effect, Cryoprotective,Effects, Cryoprotective
D005615	Freezing	Liquids transforming into solids by the removal of heat.	Melting
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D013500	Surface Tension	The force acting on the surface of a liquid, tending to minimize the area of the surface. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Interfacial Force,Interfacial Tension,Surface Tensions,Tension, Surface,Tensions, Surface
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor
D015925	Cryopreservation	Preservation of cells, tissues, organs, or embryos by freezing. In histological preparations, cryopreservation or cryofixation is used to maintain the existing form, structure, and chemical composition of all the constituent elements of the specimens.	Cryofixation,Cryonic Suspension,Cryonic Suspensions,Suspension, Cryonic