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Lysine Uptake in Cultured Trypanosoma cruzi: Interactions of Competitive Inhibitors *
Author(s) -
HAMPTON JAMES R.
Publication year - 1970
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1970.tb04734.x
Subject(s) - lysine , phenylalanine , alanine , valine , amino acid , leucine , biochemistry , stereochemistry , methionine , trypanosoma cruzi , chemistry , isoleucine , glycine , tyrosine , cysteine , histidine , non competitive inhibition , biology , enzyme , parasite hosting , world wide web , computer science
SYNOPSIS Three sites are involved in lysine transport in Trypanosoma cruzi, as inferred from interactions of inhibitory neutral amino acids. Phenylalanine and tyrosine inhibit one site; proline and the straight‐chain amino acids, alanine, methionine and cysteine inhibit another; and glycine and the branched‐chain valine, leucine, and isoleucine inhibit a 3rd. The curved rather than straight line obtained with a Lineweaver‐Burk plot of uptake rates presumably results from the functioning of qualitatively different transport sites. Blocking every site but one results in the linear double‐reciprocal plot characteristic of adsorption kinetics. The partial competitiveness of most of the inhibitions appears to denote qualitatively different sites for lysine transport and the reaction of the inhibitor with more than one site. Since most of the inhibitions were partially competitive, the specificities of the 3 lysine transport sites must overlap considerably.