User:Jonathan Cline/Notebook/Melaminometer/Technical Summary: Difference between revisions

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(New page: Melamine is an organic base and a trimer of cyanamide, with a 1,3,5-triazine skeleton. (See Triazine) Melamine combines with cyanuric acid to form melamine cyanurate. Melting point 350 ...)
 
 
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== Technical Summary of Melamine Detector ==


Melamine is an organic base and a trimer of cyanamide, with a 1,3,5-triazine skeleton. (See Triazine)  Melamine combines with cyanuric acid to form melamine cyanurate.  Melting point 350 °C.
Melamine can be metabolized by biochemical/enzymatic process in bacteria and/or other compatible organisms.  Using recombinant DNA techniques, plasmids containing genes encoding specific enzymes will be used to modify the target organism (aka: the chassis). There may be one to four enzymes required for metabolism to desired products.


http://upload.wikimedia.org/wikipedia/commons/thumb/0/05/Melamine.svg/150px-Melamine.svg.png
Melamine C3H6N6


== Metabolic Pathway ==


A 1,3,5-triazine, also called s-triazine, is an organic chemical compound whose chemical structure has a six-membered heterocyclic aromatic ring consisting of three carbon atoms and three nitrogen atoms.  triazine is one of three organic chemicals, isomeric with each other, whose empirical formula is C3H3N3.  The atoms in triazine rings are analogous to those in benzene rings, which makes triazines aromatic compounds like benzene.  The most common derivative of 1,3,5-triazine is 2,4,6-triamino-1,3,5-triazine, commonly known as melamine or cyanuramide.  2,4,6-Trichloro-1,3,5-triazine is easily hydrolyzed to cyanuric acid by heating with water at elevated temperatures.  Trichloro-1,3,5-triazine is the starting point for the manufacture of many herbicides such as simazin. Another important derivative is 2,4,6-trihydroxy-1,4,5-triazine better known as cyanuric acid. 
<pre>


http://upload.wikimedia.org/wikipedia/commons/thumb/c/c1/135TriazineStructure.png/100px-135TriazineStructure.png
melamine --(1)--> ammeline --(2)--> ammelide --(3)--> cyanuric acid
Traizine


http://upload.wikimedia.org/wikipedia/commons/e/e2/Triazine_isomers.PNG
cyanuric acid  --(4)--> biuret --(5)--> allophante --(6)--> 2 NH3 + some CO2
Triazine Rings


Cyanuric acid or 1,3,5-triazine-2,4,6-triol is a chemical compound.


http://upload.wikimedia.org/wikipedia/commons/a/a1/S-triazine-2%2C4%2C6-triol_and_s-triazine-2%2C4%2C6-trione.PNG Cyanuric acid C3H3N3O3


* (1):  melamine deaminase:triA  --^ NH4+ + H2O
* (2):  ammeline aminohydralase:triA  --^ NH4+ + H2O
* (3):  ammelide aminohydralase:trzC  --^ NH4+ + H2O
* (4):  atzD/trzD  --^ NH4+ + H2O
* (5):  atzE 
* (6):  atzF 


Melamine cyanurate, also known as melamine-cyanuric acid adduct or melamine-cyanuric acid complex, is a crystalline complex formed from a 1:1 mixure of melamine and cyanuric acid. The substance is not a salt despite its non-systematic name melamine cyanurate. The complex is held together by an extensive two-dimensional network of hydrogen bonds.
</pre>


http://upload.wikimedia.org/wikipedia/commons/thumb/4/4d/Melamine-cyanuric_acid_chemical_structure_color.png/200px-Melamine-cyanuric_acid_chemical_structure_color.png Melamine-cyanuric acid complex C6H9N9O3 (C3H6N6·C3H3N3O3)
 
== Detection Threshold ==
 
From the U.S. FDA standards,
* a level of melamine and its analogues above 2.5 mg/kg is indicative of food adulteration.
* This 2.5 ppm represents consumption of 0.063 mg/kg bw/d.
 
The threshold needed for detection is (x mMol) or no greater than 2.5 ppm.
 
== Logical operation ==
 
Desired logical operation:
 
<pre>
 
if [ melamine plus cyanuric acid > threshold ]
then
  amplify
  express RFP  ; or other reporter
  stop
else
  repress RFP  ; or other reporter
  stop
endif
 
</pre>

Latest revision as of 04:21, 16 October 2008

Technical Summary of Melamine Detector

Melamine can be metabolized by biochemical/enzymatic process in bacteria and/or other compatible organisms. Using recombinant DNA techniques, plasmids containing genes encoding specific enzymes will be used to modify the target organism (aka: the chassis). There may be one to four enzymes required for metabolism to desired products.


Metabolic Pathway


melamine --(1)--> ammeline --(2)--> ammelide --(3)--> cyanuric acid 

cyanuric acid  --(4)--> biuret --(5)--> allophante --(6)--> 2 NH3 + some CO2



* (1):  melamine deaminase:triA  --^ NH4+ + H2O
* (2):  ammeline aminohydralase:triA  --^ NH4+ + H2O
* (3):  ammelide aminohydralase:trzC  --^ NH4+ + H2O
* (4):  atzD/trzD  --^ NH4+ + H2O
* (5):  atzE  
* (6):  atzF


Detection Threshold

From the U.S. FDA standards,

  • a level of melamine and its analogues above 2.5 mg/kg is indicative of food adulteration.
  • This 2.5 ppm represents consumption of 0.063 mg/kg bw/d.

The threshold needed for detection is (x mMol) or no greater than 2.5 ppm.

Logical operation

Desired logical operation: 


if [ melamine plus cyanuric acid > threshold ] 
then
  amplify
  express RFP  ; or other reporter
  stop
else
  repress RFP  ; or other reporter
  stop
endif
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