Biomaterial Database

Estimates and implications of co-operativity for enzyme kinetics in the intact liver: method of flow invariants. 1983

L Bass

For substrates rapidly equilibrated between blood and liver cells, steady-state co-operative enzyme kinetics determines combinations of inlet and outlet substrate concentrations which do not change with the rate of blood flow recirculating through an isolated perfused liver. The mathematical forms of these combinations (here called flow invariants) are different for each value of the Hill co-operativity constant which can therefore be estimated, on a set of intact perfused preparations, from that flow invariant which is stochastically least dependent on experimental changes in the flow rate. This estimate, made in a narrow range of substrate concentrations, is illustrated using previously published data on the phosphorylation of galactose by galactokinase in rat liver. Changes (if any) of hepatocellular Hill constants in liver disease could be of clinical interest. A conspicuous difference between effects of negative and positive cooperativity in the intact perfused organ is found: for negative (but not for positive) co-operativity, complete extraction of the substrate in a single pass through a shunt-free liver is predicted from Hill's equation for a specified range of finite input concentrations and flow rates. Substrates with negative co-operativity in vivo would therefore facilitate the quantification of intrahepatic shunts.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008102	Liver Circulation	The circulation of BLOOD through the LIVER.	Hepatic Circulation,Circulation, Liver,Circulation, Hepatic
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D010477	Perfusion	Treatment process involving the injection of fluid into an organ or tissue.	Perfusions
D005690	Galactose	An aldohexose that occurs naturally in the D-form in lactose, cerebrosides, gangliosides, and mucoproteins. Deficiency of galactosyl-1-phosphate uridyltransferase (GALACTOSE-1-PHOSPHATE URIDYL-TRANSFERASE DEFICIENCY DISEASE) causes an error in galactose metabolism called GALACTOSEMIA, resulting in elevations of galactose in the blood.	D-Galactose,Galactopyranose,Galactopyranoside,D Galactose
D005693	Galactosemias	A group of inherited enzyme deficiencies which feature elevations of GALACTOSE in the blood. This condition may be associated with deficiencies of GALACTOKINASE; UDPGLUCOSE-HEXOSE-1-PHOSPHATE URIDYLYLTRANSFERASE; or UDPGLUCOSE 4-EPIMERASE. The classic form is caused by UDPglucose-Hexose-1-Phosphate Uridylyltransferase deficiency, and presents in infancy with FAILURE TO THRIVE; VOMITING; and INTRACRANIAL HYPERTENSION. Affected individuals also may develop MENTAL RETARDATION; JAUNDICE; hepatosplenomegaly; ovarian failure (PRIMARY OVARIAN INSUFFICIENCY); and cataracts. (From Menkes, Textbook of Child Neurology, 5th ed, pp61-3)	Galactokinase Deficiency Disease,Galactose-1-Phosphate Uridyl-Transferase Deficiency Disease,UDPglucose 4-Epimerase Deficiency Disease,Classic Galactosemia,Deficiency Disease, Galactokinase,Deficiency Disease, Galactose-1-Phosphate Uridyl-Transferase,Deficiency Disease, UDP-Galactose-4-Epimerase,Deficiency Disease, UDPglucose 4-Epimerase,Epimerase Deficiency Galactosemia,GALE Deficiency,GALK Deficiency,GALT Deficiency,Galactokinase Deficiency,Galactose Epimerase Deficiency,Galactose-1-Phosphate Uridyltransferase Deficiency,Galactose-1-Phosphate Uridylyltransferase Deficiency,Galactosemia,Galactosemia 2,Galactosemia 3,Galactosemia III,Galactosemia, Classic,Hereditary Galactokinase Deficiency,UDP-Galactose-4-Epimerase Deficiency,UDP-Galactose-4-Epimerase Deficiency Disease,UDPGlucose Hexose-1-Phosphate Uridylyltransferase Deficiency,UTP Hexose-1-Phosphate Uridylyltransferase Deficiency,UTP-Hexose-1-Phosphate Uridylyltransferase Deficiency Disease,Classic Galactosemias,Deficiencies, GALE,Deficiencies, GALK,Deficiencies, GALT,Deficiencies, Galactokinase,Deficiencies, Galactose Epimerase,Deficiencies, Galactose-1-Phosphate Uridyltransferase,Deficiencies, Galactose-1-Phosphate Uridylyltransferase,Deficiencies, Hereditary Galactokinase,Deficiencies, UDP-Galactose-4-Epimerase,Deficiency Disease, Galactose 1 Phosphate Uridyl Transferase,Deficiency Disease, UDP Galactose 4 Epimerase,Deficiency Disease, UDPglucose 4 Epimerase,Deficiency Diseases, UDP-Galactose-4-Epimerase,Deficiency Galactosemia, Epimerase,Deficiency Galactosemias, Epimerase,Deficiency, GALE,Deficiency, GALK,Deficiency, GALT,Deficiency, Galactokinase,Deficiency, Galactose Epimerase,Deficiency, Galactose-1-Phosphate Uridyltransferase,Deficiency, Galactose-1-Phosphate Uridylyltransferase,Deficiency, Hereditary Galactokinase,Deficiency, UDP-Galactose-4-Epimerase,Epimerase Deficiency Galactosemias,GALE Deficiencies,GALK Deficiencies,GALT Deficiencies,Galactokinase Deficiencies,Galactokinase Deficiencies, Hereditary,Galactokinase Deficiency Diseases,Galactokinase Deficiency, Hereditary,Galactose 1 Phosphate Uridyl Transferase Deficiency Disease,Galactose 1 Phosphate Uridyltransferase Deficiency,Galactose 1 Phosphate Uridylyltransferase Deficiency,Galactose Epimerase Deficiencies,Galactose-1-Phosphate Uridyltransferase Deficiencies,Galactose-1-Phosphate Uridylyltransferase Deficiencies,Galactosemia 2s,Galactosemia 3s,Galactosemia IIIs,Galactosemia, Epimerase Deficiency,Galactosemias, Classic,Galactosemias, Epimerase Deficiency,Hereditary Galactokinase Deficiencies,UDP Galactose 4 Epimerase Deficiency,UDP Galactose 4 Epimerase Deficiency Disease,UDP-Galactose-4-Epimerase Deficiencies,UDP-Galactose-4-Epimerase Deficiency Diseases,UDPGlucose Hexose 1 Phosphate Uridylyltransferase Deficiency,UDPglucose 4 Epimerase Deficiency Disease,UTP Hexose 1 Phosphate Uridylyltransferase Deficiency,UTP Hexose 1 Phosphate Uridylyltransferase Deficiency Disease,Uridyltransferase Deficiencies, Galactose-1-Phosphate,Uridyltransferase Deficiency, Galactose-1-Phosphate,Uridylyltransferase Deficiencies, Galactose-1-Phosphate,Uridylyltransferase Deficiency, Galactose-1-Phosphate
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
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus