| Autor: |
LAWRENCE, Christopher C., SOBEY, Wendy J., FIELD, Robert A., BALDWIN, Jack E., SCHOFIELD, Christopher J. |
| Zdroj: |
Biochemical Journal; January 1996, Vol. 313 Issue: 1 p185-191, 7p |
| Abstrakt: |
Proline 4-hydroxylase is a 2-oxoacid, ferrous-ion-dependent dioxygenase involved in the biosynthesis of the secondary metabolite etamycin. The purification, in low yield, of proline 4-hydroxylase from Streptomyces griseoviridus P8648 to near apparent homogeneity and its initial characterization are reported. In most respects proline 4-hydroxylase is a typical member of the 2-oxoacid-dependent dioxygenase family. It is monomeric (Mr approx. 38000) (by gel filtration on Superdex-G75) and has typically strict requirements for ferrous ion and 2-oxoglutarate. The enzyme was inhibited by aromatic analogues of 2-oxoglutarate. L-Proline-uncoupled turnover of 2-oxoglutarate to succinate and CO2 was observed. The addition of L-ascorbate did not stimulate L-proline-coupled turnover of 2-oxoglutarate, but did stimulate L-proline-uncoupled turnover. L-Ascorbate caused a time-dependent inhibition of L-proline hydroxylation. The enzyme was completely inactivated by preincubation with diethyl pyrocarbonate under histidine-modifying conditions. This inactivation could be partially prevented by the inclusion of L-proline and 2-oxoglutarate in the preincubation mixture, suggesting the presence of histidine residue(s) at the active site. |
| Databáze: |
Supplemental Index |
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