Biomaterial Database

Diacylglycerol partitioning and mixing in detergent micelles: relevance to enzyme kinetics. 1997

C Zhou, and M F Roberts

Mekert Chemistry Center, Boston College, Chestnut Hill, MA 02167, USA.

For many of the enzymes that utilize or produce diacylglycerols, detergent mixed micelles are often used in assay systems to solubilize the lipophilic substrates or products. The assumption is often made that the diacylglycerol (DAG) is solubilized and well mixed throughout the population of micelles during the time course of the assay. In the present work the partitioning and exchange dynamics of diacylglycerols (from dihexanoyl-DAG to didecanoyl-DAG) in a variety of detergent micelles have been studied by NMR and fluorescence methods. In all detergents, the longer the DAG chain lengths, the more detergent is required for solubilization. However, efficiency of solubilization varies tremendously with Triton X-100 the most efficient (i.e. the least detergent is required), and deoxycholate the least efficient in solubilizing DAG. The mixing and exchange dynamics of pyrene-labeled DAG molecules in these micelles (measured by stopped-flow fluorescence) were fastest for Triton X-100 and slowest with charged bile salt micelles. Of the detergent systems characterized, Triton X-100 appears to be the optimal detergent for use in assays of enzymes that interact with DAG (beta-octylglucoside and diheptanoylphosphatidylcholine have good exchange dynamics, but higher amounts of these detergents are needed to solubilize DAG). Bile salt micelles provide the least solubilization and the slowest exchange kinetics (so slow that this could be a significant problem in some enzyme assays). This information on DAG behavior in micelles is discussed with respect to assays of an enzyme that generates DAG as product (phospholipase C) and one that uses DAG as substrate (DAG kinase). Although slow exchange of DAG occurs in some micelle systems, this does not appear to be a rate-limiting step in the kinetics for either of these enzymes.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008823	Micelles	Particles consisting of aggregates of molecules held loosely together by secondary bonds. The surface of micelles are usually comprised of amphiphatic compounds that are oriented in a way that minimizes the energy of interaction between the micelle and its environment. Liquids that contain large numbers of suspended micelles are referred to as EMULSIONS.	Micelle
D008968	Molecular Conformation	The characteristic three-dimensional shape of a molecule.	Molecular Configuration,3D Molecular Structure,Configuration, Molecular,Molecular Structure, Three Dimensional,Three Dimensional Molecular Structure,3D Molecular Structures,Configurations, Molecular,Conformation, Molecular,Conformations, Molecular,Molecular Configurations,Molecular Conformations,Molecular Structure, 3D,Molecular Structures, 3D,Structure, 3D Molecular,Structures, 3D Molecular
D009682	Magnetic Resonance Spectroscopy	Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).	In Vivo NMR Spectroscopy,MR Spectroscopy,Magnetic Resonance,NMR Spectroscopy,NMR Spectroscopy, In Vivo,Nuclear Magnetic Resonance,Spectroscopy, Magnetic Resonance,Spectroscopy, NMR,Spectroscopy, Nuclear Magnetic Resonance,Magnetic Resonance Spectroscopies,Magnetic Resonance, Nuclear,NMR Spectroscopies,Resonance Spectroscopy, Magnetic,Resonance, Magnetic,Resonance, Nuclear Magnetic,Spectroscopies, NMR,Spectroscopy, MR
D010738	Type C Phospholipases	A subclass of phospholipases that hydrolyze the phosphoester bond found in the third position of GLYCEROPHOSPHOLIPIDS. Although the singular term phospholipase C specifically refers to an enzyme that catalyzes the hydrolysis of PHOSPHATIDYLCHOLINE (EC 3.1.4.3), it is commonly used in the literature to refer to broad variety of enzymes that specifically catalyze the hydrolysis of PHOSPHATIDYLINOSITOLS.	Lecithinase C,Phospholipase C,Phospholipases, Type C,Phospholipases C
D003902	Detergents	Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.	Cleansing Agents,Detergent Pods,Laundry Detergent Pods,Laundry Pods,Syndet,Synthetic Detergent,Agent, Cleansing,Agents, Cleansing,Cleansing Agent,Detergent,Detergent Pod,Detergent Pod, Laundry,Detergent Pods, Laundry,Detergent, Synthetic,Detergents, Synthetic,Laundry Detergent Pod,Laundry Pod,Pod, Detergent,Pod, Laundry,Pod, Laundry Detergent,Pods, Detergent,Pods, Laundry,Pods, Laundry Detergent,Synthetic Detergents
D004075	Diglycerides	Glycerides composed of two fatty acids esterified to the trihydric alcohol GLYCEROL. There are two possible forms that exist: 1,2-diacylglycerols and 1,3-diacylglycerols.	Diacylglycerol,Diacylglycerols
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D005960	Glucosides	A GLYCOSIDE that is derived from GLUCOSE.	Glucoside
D001409	Bacillus cereus	A species of rod-shaped bacteria that is a common soil saprophyte. Its spores are widespread and multiplication has been observed chiefly in foods. Contamination may lead to food poisoning.