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Studies on the mechanism of zinc uptake by human fibroblasts.

Version 2 2024-06-03, 11:05
Version 1 2017-08-01, 15:07
journal contribution
posted on 2024-06-03, 11:05 authored by Leigh AcklandLeigh Ackland, DM Danks, HJ McArdle
The mechanisms of zinc uptake from a complete culture medium by human fibroblasts have been studied. The metal is accumulated in a biphasic pattern; an initial rapid phase followed by a slower linear phase. We suggest that the former represents binding to carriers or receptors on the cell surface followed by uptake to within the cell, or at least to a compartment inaccessible to proteolytic digestion. The uptake correlates well with estimates of the zinc requirement of a growing fibroblast. The process of uptake is saturable, with an apparent association constant of 1.1 X 10(7) M-1. Interestingly, there appears to be a very large number of binding sites, 2 X 10(7) per cell. No explanation for this observation is immediately apparent. The mechanism of uptake is not dependent on metabolic energy, or at least on ATP levels within the cell, but N-ethyl maleimide does block uptake in a dose-dependent manner. Weak bases and ionophores, apart from nigericin, do not affect uptake. The results suggest that zinc is not taken up by a receptor-mediated endocytic pathway as has been described for transferrin and iron.

History

Journal

Journal of Cellular Physiology

Volume

135

Pagination

521-526

Location

United States

ISSN

0021-9541

eISSN

1097-4652

Language

eng

Publication classification

CN.1 Other journal article

Issue

3

Publisher

Wiley