What are the sources and characteristics of PG?

References:

1, The characteristics of protein-glutaminase from an isolated Chryseobacterium cucumeris strain and its deamidation application. Frontiers | The characteristics of protein-glutaminase from an isolated Chryseobacterium cucumeris strain and its deamidation application (frontiersin.org) 2, L-Glutamine-, peptidyl- and protein-glutaminases: structural features and applications in the food industry. l-Glutamine-, peptidyl- and protein-glutaminases: structural features and applications in the food industry | SpringerLink 3, The characteristics of protein-glutaminase from an isolated Chryseobacterium cucumeris strain and its deamidation application. The characteristics of protein-glutaminase from an isolated Chryseobacterium cucumeris strain and its deamidation application – DOAJ