Ec. King et al., Enzymatic breakdown of poly-gamma-D-glutamic acid in Bacillus licheniformis: Identification of a polyglutamyl gamma-hydrolase enzyme, BIOMACROMOL, 1(1), 2000, pp. 75-83
A polyglutamyl gamma -hydrolase enzyme has been identified which catalyses
the hydrolytic breakdown of poly-gamma -D-glutamic acid (PGA) from Bacillus
licheniformis 9945a. The enzyme was found to be physically associated with
the polymer and was activated by Zn2+ or Ca2+ salts. The enzyme can be sol
ubilized from the polymer by treatment with 0.5% SDS and 1 mM ZnCl2 and can
then be renatured onto exogenous PGA upon dilution below the detergent cri
tical micellar concentration. The enzyme was partially purified by affinity
chromatography, using immobilized PGA. Peptide thioesters containing one a
nd two gamma -glutamyl units were synthesized as potential chromogenic subs
trates but showed no activity with the solubilized enzyme. Examination of C
-14-labeled reaction products indicated that the enzyme is an endo-type hyd
rolase.