title: The effect of histidine and cysteine on zinc influx into rat and human erythrocytes.
abstract: 1. The effect of histidine and cysteine on the initial rate of zinc influx into rat and human erythrocytes in the presence of bovine serum albumin has been investigated. 2. The L-enantiomers of both amino acids promoted zinc influx into rat erythrocytes in a dose-dependent manner. L-Histidine, but not L-cysteine, also promoted zinc uptake into human erythrocytes. D-Histidine did not promote zinc uptake in either rat or human erythrocytes. In rat erythrocytes D-cysteine was significantly less effective than L-cysteine. 3. The stimulation of zinc influx into rat erythrocytes by 20 mM L-histidine was approximately 4.1 times that seen with human erythrocytes. 4. The influx of zinc in the presence of varying concentrations of L-histidine was linearly related to the calculated concentration of the zinc-bis-histidine complex but not to that of the zinc-mono-histidine complex or the free ionic zinc concentration. 5. These results are discussed in relation to the nature of the transport mechanisms involved.
authors.affiliation: Department of Physiology and Pharmacology, University of Southampton, UK.
authors.forename: N M
authors.initials: NM
authors.lastname: Horn
authors.forename: A L
authors.initials: AL
authors.lastname: Thomas
authors.forename: J D
authors.initials: JD
authors.lastname: Tompkins
mesh_terms: D000818:Animals; D003545:Cysteine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism; D006639:Histidine / Q000494:pharmacology*; D006801:Humans; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D015032:Zinc / Q000378:metabolism*
chemical_list: D006639:Histidine; D015032:Zinc; D003545:Cysteine