Folate-independent pathway

Mathematical Principles

View previous presentation in the modeling of photosynthetic HCHO assimilation pathway:

Photosynthetic HCHO assimilation pathway (HPS/PHI)

Results

By changing the value of those parameters (k1, k2 … ), we obtained the relationship (Fig.3) between the concentration of different components (Ru5P, F6P and HCHO) versus the time.

Fig.3 The diagram of concentration versus time. A for Ru5P and F6P, B for HCHO and C for those three components

From Fig.3, we found that the components tend to be the steady state when time goes by. Means that when the formaldehyde into the plant cell, the original steady state would be broken, but after a period of time, the cells will restore homeostasis which indicated that the indoor formaldehyde has been absorbed by the plant. For figure 3B, in the initial stage, formaldehydewill continue to grow due to the delayed effects of reaction; subsequently,the concentration of formaldehyde begins to decrease with time and finally tends to be the steady state.

Folate-independent pathway

The metabolism of folate-independent pathway was shown on Fig.1.

Fig.1 Schematic diagram offormaldehyde metabolic pathways in plant. SMM cycle, S-methylmethionine cycle

Simplify the system (Fig.2), consist of the input of HCHO and the recycle of HCOOH:

Fig.2 A simplified version of folate-independent pathway. FTS, 10-Formyl-THF synthetase.

Some research indicated that the activity of FTS in tobacco was low and we ignored this pathway in our system. The chemical reactions of this formaldehyde metabolism are shown below.

(1)

where parameter a is a constant which means the proportion of HCOOH into the calvin cycle. The dynamic equation group of the reaction system can be obtained:

(2)

Results

By changing the value of the parameters (k0, k1 … ), we obtained the relationship (Fig.3) between the concentration of different components (HCOOH and HCHO) versus the time.

Fig.3 The diagram of concentration versus time.

We found that the components tend to be the steady state when time goes by. Means that when the formaldehyde into the plant cell, the original steady state was broken, but after a period of time, the cells will restore homeostasis.

Link to other modeling

Photosynthetic HCHO assimilation pathway (HPS/PHI)
Modeling of stoma (AtAHA2)