Biomaterial Database

The phospholipid-dependence of uridine diphosphate glucuronyltransferase. Temperature-dependence of microsomal enzyme activity (reverse reaction). 1980

J Cummings, and A B Graham, and G C Wood

Arrhenius plots of the non-latent UDP-glucuronlytransferase reverse reaction (p-nitrophenyl glucuronide donor) activity of guinea-pig microsomal membranes prepared with 15 mM-KCl were linear from 5 to 40 degrees C. These plots for other preparations from guinea-pig and rat liver (i.e. preparations that show transferase latency) exhibited two linear regions intersecting at a transition point near 19--21 degrees C. This discontinuity was abolished when latency was removed by treating the membranes with perturbants of phospholipid-bilayer structure. Thus the temperature-depdendnces of the reverse reaction catalysed by the enzymes of these various preparations are similar to those of the corresponding forward reactions [Pechey, Graham & Wood (1978) Biochem. J. 175, 115--1124]. Perturbants activated the enzyme of KCl-prepared guinea-pig microsomal membranes only slightly and caused no significant alteration to Arrhenius plots of its forward or reverse reaction activities. These results support the 'compartmentation' theory of UDP-glucuronyltransferase lactency.

UI	MeSH Term	Description	Entries
D007425	Intracellular Membranes	Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.	Membranes, Intracellular,Intracellular Membrane,Membrane, Intracellular
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008041	Linoleic Acids	Eighteen-carbon essential fatty acids that contain two double bonds.	Acids, Linoleic
D008244	Lysophosphatidylcholines	Derivatives of PHOSPHATIDYLCHOLINES obtained by their partial hydrolysis which removes one of the fatty acid moieties.	Lysolecithin,Lysolecithins,Lysophosphatidylcholine
D008862	Microsomes, Liver	Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.	Liver Microsomes,Liver Microsome,Microsome, Liver
D010741	Phospholipases A	Phospholipases that hydrolyze one of the acyl groups of phosphoglycerides or glycerophosphatidates.
D010743	Phospholipids	Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.	Phosphatides,Phospholipid
D011092	Polyethylene Glycols	Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.	Macrogols,Polyoxyethylenes,Carbowax,Macrogol,Polyethylene Glycol,Polyethylene Oxide,Polyethyleneoxide,Polyglycol,Glycol, Polyethylene,Glycols, Polyethylene,Oxide, Polyethylene,Oxides, Polyethylene,Polyethylene Oxides,Polyethyleneoxides,Polyglycols,Polyoxyethylene
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
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