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Stimulation by glutamine of the formation of N 6 ‐hydroxylysine in a cell‐free extract from aerobacter aerogenes 62‐1
Author(s) -
Jackson G. E. D.,
Parniak M. A.,
Murray G. J.,
Viswanatha T.
Publication year - 1984
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240240409
Subject(s) - glutamine , biochemistry , azaserine , chemistry , incubation , biology , amino acid
Glutamine may serve as an activator and/or regulator of the N 6 ‐hydroxylase (E.C. 1.14.99) of Aerobacter aerogenes 62‐1. Activation and stabilization of N 6 ‐hydroxylase activity was observed both in vivo and in vitro. Growth in a glutamine‐supplemented medium resulted in (1) maximum N 6 ‐hydroxylase activity at an earlier stage of growth and (2) higher N 6 ‐hydroxylase activity and continued aerobactin synthesis into stationary phase. Storage of P2 in the presence of L‐glutamine (1 mM) significantly increased the lifetime of the labile N 6 ‐hydroxylase activity. Inclusion of L‐glutamine in the incubation mixture typically resulted in a 2‐3‐fold activation of the hydroxylase activity. The stimulatory effect of glutamine was independent of and additive to the enhancement of N 6 ‐hydroxylation by the active component(s) in the supernatant, S2 fraction. Glutamic acid‐γ‐semihydrazide activated slightly in the absence of glutamine but activation of the system by glutamine was decreased by this compound. Azaserine was shown to be an uncompetitive inhibitor with respect to lysine and this inhibition was not reversed by glutamine.