title: A deficiency of hypoxanthine phosphoribosyltransferase in a sycamore callus resistant to azaguanine.
abstract: Sycamore (Acer pseudoplatanus L.) calluses resistant to azaguanine were isolated after mutagenesis with nitrosoguanidine. One callus SNC61 was highly variable in its growth on 10 μg/ml azaguanine and it was concluded that its resistance was not due to a stable alteration in the callus. Another callus SNE31 was isolated after 4.5 months culture in 0.5 or 1 μg/ml azaguanine which had a 10-fold increase in resistance to azaguanine. This was shown to be accompanied by a reduction to 50% of the normal level of hypoxanthine phosphoribosyltransferase (E.C.2.4.2.8).
authors.affiliation: Department of Biochemistry, University of Cambridge, CB2 1 QW, Cambridge, UK.
authors.forename: S W
authors.initials: SW
authors.lastname: Bright
authors.forename: D H
authors.initials: DH
authors.lastname: Northcote