Biomaterial Database

Active carrier-mediated transport of melphalan by two separate amino acid transport systems in LPC-1 plasmacytoma cells in vitro. 1979

G J Goldenberg, and H Y Lam, and A Begleiter

Previous studies have shown that uptake of several alkylating agents occurs by independent transport mechanisms. Uptake of one of these agents, the phenylalanine derivative of nitrogen mustard (melphalan), has been investigated in LPC-1 plasmacytoma cells in vitro. Evidence suggesting that melphalan uptake is an active process is that uptake of free intact melphalan proceeds "uphill" against a concentration gradient, is temperature- and sodium-dependent, and is inhibited by several metabolic antagonists. Other findings supporting the concept that melphalan uptake is carrier-mediated is that uptake follows biphasic Michaelis-Menten kinetics, is chemically specific, and is mediated by at least two separate amino acid transport systems. Uptake by one system was sensitive to DL-beta-2-aminobicyclo[2,2,1]-heptane-2-carboxylic acid, was sodium-independent, and appeared to be mediated by system L. The second unassigned system was characterized by sodium dependence, insensitivity to 2-aminoisobutyric acid and 2-(methylamino)isobutyric acid, and was inhibited by alanine, serine, cysteine, and other amino acids.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D007930	Leucine	An essential branched-chain amino acid important for hemoglobin formation.	L-Leucine,Leucine, L-Isomer,L-Isomer Leucine,Leucine, L Isomer
D008558	Melphalan	An alkylating nitrogen mustard that is used as an antineoplastic in the form of the levo isomer - MELPHALAN, the racemic mixture - MERPHALAN, and the dextro isomer - MEDPHALAN; toxic to bone marrow, but little vesicant action; potential carcinogen.	Medphalan,Merphalan,Phenylalanine Mustard,Sarcolysine,Sarkolysin,4-(Bis(2-chloroethyl)amino)phenylalanine,Alkeran,L-PAM,Mustard, Phenylalanine
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D005973	Glutamine	A non-essential amino acid present abundantly throughout the body and is involved in many metabolic processes. It is synthesized from GLUTAMIC ACID and AMMONIA. It is the principal carrier of NITROGEN in the body and is an important energy source for many cells.	D-Glutamine,L-Glutamine,D Glutamine,L Glutamine
D000596	Amino Acids	Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.	Amino Acid,Acid, Amino,Acids, Amino
D001693	Biological Transport, Active	The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.	Active Transport,Uphill Transport,Active Biological Transport,Biologic Transport, Active,Transport, Active Biological,Active Biologic Transport,Transport, Active,Transport, Active Biologic,Transport, Uphill