Registration Dossier

Ecotoxicological information

Biotransformation and kinetics

Currently viewing:

Administrative data

Endpoint:
biotransformation and kinetics
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Appropriate publication. Not according to any guideline.
Cross-reference
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1982

Materials and methods

Principles of method if other than guideline:
The degradative pathway of melamine by Pseudomonas sp. was examined and the degradation products were identified.
GLP compliance:
not specified
Type of medium:
aquatic

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Purity >= 98 %, Melamine obtained from Fluka, Buchs, Switzerland

Results and discussion

Transformation products:
yes
Identity of transformation productsopen allclose all
No.:
#1
Reference
Reference substance name:
Unnamed
IUPAC name:
ammeline
Identifier:
common name
Identity:
ammeline
No.:
#2
Reference
Reference substance name:
Unnamed
IUPAC name:
ammelide
Identifier:
common name
Identity:
ammelide
No.:
#3
Reference
Reference substance name:
Unnamed
Inventory number:
InventoryMultipleMappingImpl [inventoryEntryValue=EC 203-618-0]
IUPAC name:
1,3,5-triazine-2,4,6-triol
Identity:
1,3,5-Triazine-2,4,6(1H,3H,5H)-trione
CAS number:
108-80-5
Molecular formula:
C3H3N3O3
Molecular weight:
129.074
SMILES notation:
Oc1nc(O)nc(O)n1
InChl:
InChI=1/C3H3N3O3/c7-1-4-2(8)6-3(9)5-1/h(H3,4,5,6,7,8,9)
No.:
#4
Reference
Reference substance name:
Unnamed
IUPAC name:
carbon dioxide and ammonia
Identifier:
common name
Identity:
carbon dioxide and ammonia

Any other information on results incl. tables

The bacterium Pseudomonas sp. strain A grew with melamine, ammeline, ammelide, cyanuric acid or NH4+ as sole source of nitrogen, and each substrate was entirely metabolized. Utilization of ammeline, ammelide, cyanuric acid or NH4+ was concomitant with growth. But with melamine as substrate, a transient intermediate was detected, which was identified as ammeline by three methods.

Enzymes from strain A were separated by chromatography on DEAE-cellulose and four activities were examined.

Melamine was converted stoichiometrically into equimolar amounts of ammeline and NH4+.

Ammeline was converted stoichiometrically into equimolar amounts of ammelide and NH4+, ammelide was identified by four methods.

Ammelide was converted stoichiometrically into equimolar amounts of cyanuric acid and NH4+, cyanuric acid was identified by four methods.

Cyanuric acid was converted by an enzyme preparation into an unidentified product with negligible release of NH4+.

The specific activities of the degradative enzymes (>= 0.3 mkat/kg of protein) were high enough to explain the growth rate of the organism.

The bacterium converted 0.4 mM-melamine anaerobically into 2.3 mM NH4+.

Two other pseudomonas and two strains of Klebsiella pneumoniae were also examined, with similar results.

The degradative pathway of melamine appears to be hydrolytic, and proceeds by three successive deaminations to cyanuric acid, which is further metabolized.

Applicant's summary and conclusion

Conclusions:
The anaerobical deamination of melamine -> ammeline -> ammelide -> cyanuric acid is described for 3 strains of Pseudomonas and 2 strain sof Klebsiella.
(A similar degradation by activated sludge was described by Fimberger 1997, see Chapter 5.2.1.)
Executive summary:

The degradative pathway of melamine (1,3,5-triazine-2,4,6-triamine) was examined in Pseudomonas sp. strain A (and other microorganisms).

The bacterium grew with melamine, ammeline, ammelide, cyanuric acid or NH4+ as sole source of nitrogen, and each substrate was entirely metabolized. Utilization of ammeline, ammelide, cyanuric acid or NH4+ was concomitant with growth. But with melamine as substrate, a transient intermediate was detected, which was identified as ammeline by three methods.

Enzymes from strain A were separated by chromatography on DEAE-cellulose and four activities were examined.

Melamine was converted stoichiometrically into equimolar amounts of ammeline and NH4+.

Ammeline was converted stoichiometrically into equimolar amounts of ammelide and NH4+, ammelide was identified by four methods.

Ammelide was converted stoichiometrically into equimolar amounts of cyanuric acid and NH4+, cyanuric acid was identified by four methods.

Cyanuric acid was converted by an enzyme preparation into an unidentified product with negligible release of NH4+.

The specific activities of the degradative enzymes (>= 0.3 mkat/kg of protein) were high enough to explain the growth rate of the organism.

The bacterium converted 0.4 mM-melamine anaerobically into 2.3 mM NH4+.

Two other pseudomonas and two strains of Klebsiella pneumoniae were also examined, with similar results.

The degradative pathway of melamine appears to be hydrolytic, and proceeds by three successive deaminations to cyanuric acid, which is further metabolized.