PMID- 11693932
OWN - NLM
STAT- MEDLINE
DCOM- 20020408
LR  - 20190916
IS  - 0175-7598 (Print)
IS  - 0175-7598 (Linking)
VI  - 57
IP  - 1-2
DP  - 2001 Oct
TI  - Over-production of hydantoinase and N-carbamoylamino acid amidohydrolase enzymes 
      by regulatory mutants of Agrobacterium tumefaciens.
PG  - 43-9
AB  - While the hydantoin-hydrolysing enzymes from Agrobacterium strains are used as 
      biocatalysts in the commercial production of D-p-hydroxyphenylglycine, they are 
      now mostly produced in heterologous hosts such as Escherichia coli. This is due 
      to the fact that the activity of these enzymes in the native strains is tightly 
      regulated by growth conditions. Hydantoinase and N-carbamoylamino acid 
      amidohydrolase (NCAAH) activities are induced when cells are grown in the 
      presence of hydantoin or an hydantoin analogue, and in complete medium, enzyme 
      activity can be detected only in early stationary growth phase. In this study, 
      the ability of Agrobacterium tumefaciens RU-OR cells to produce active enzymes 
      was found to be dependent upon the choice of nitrogen source and the presence of 
      inducer, 2-thiouracil, in the growth medium. Growth with (NH4)2SO4 as the 
      nitrogen source repressed the production of both enzymes (nitrogen repression) 
      and also resulted in a rapid, but reversible loss of hydantoinase activity in 
      induced cells (ammonia shock). Mutant strains with inducer-independent production 
      of the enzymes and/or altered response to nitrogen control were isolated. Of 
      greatest importance for industrial application was strain RU-ORPN1F9, in which 
      hydantoinase and NCAAH enzyme activity was inducer-independent and no longer 
      sensitive to nitrogen repression or ammonia shock. Such mutants offer the 
      potential for native enzyme production levels equivalent to those achieved by 
      current heterologous expression systems.
FAU - Hartley, C J
AU  - Hartley CJ
AD  - Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, 
      South Africa.
FAU - Manford, F
AU  - Manford F
FAU - Burton, S G
AU  - Burton SG
FAU - Dorrington, R A
AU  - Dorrington RA
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Germany
TA  - Appl Microbiol Biotechnol
JT  - Applied microbiology and biotechnology
JID - 8406612
RN  - EC 3.5.- (Amidohydrolases)
RN  - EC 3.5.1.- (N-carbamoylamino acid amidohydrolase)
RN  - EC 3.5.2.2 (dihydropyrimidinase)
SB  - IM
MH  - Agrobacterium tumefaciens/*enzymology/genetics
MH  - Amidohydrolases/*biosynthesis/genetics
MH  - *Mutation
MH  - Stereoisomerism
EDAT- 2001/11/06 10:00
MHDA- 2002/04/09 10:01
CRDT- 2001/11/06 10:00
PHST- 2001/11/06 10:00 [pubmed]
PHST- 2002/04/09 10:01 [medline]
PHST- 2001/11/06 10:00 [entrez]
AID - 10.1007/s002530100719 [doi]
PST - ppublish
SO  - Appl Microbiol Biotechnol. 2001 Oct;57(1-2):43-9. doi: 10.1007/s002530100719.