Chapter 21 : Biosynthesis of Amino Acids, Nucleotides, …

Compartmentalisation of the tetrapyrrole biosynthetic pathway and chlorophyll catabolic pathway. The second site of haem synthesis in plants, proposed to be taking place in mitochondria, is indicated by the question mark.

12. Woodward’s Synthesis of Chlorophyll - Chemistry …

A branched pathway for light-dependent chlorophyll biosynthesis in Arabidopsis thaliana.

Biosynthesis Fatty acids | Biosynthesis | Fatty Acid

Plastids are a group of organelles that are characteristic of plant cells. They have derived in an endosymbiotic event from a cyanobacterial ancestor and still exhibit many prokaryotic features. Plastids are able to perform many specialised functions that are essential for plant growth and development, such as photosynthesis, nitrate and sulfate assimilation, the synthesis of amino acids and of fatty acids, storage of carbohydrates and lipids or the formation of colours in some fruits and flowers. To accomplish this, their membrane systems exert specialised transport functions, including the import and sorting of proteins and the exchange of metabolites in case of the two envelope membranes, as well as proton and electron transport in the case of the thylakoid membranes of chloroplasts. Moreover, plastids communicate with the nucleus by retrograde signalling to adjust the expression of nuclear genes according to the metabolic and developmental state of the organelle.

Chlorophyll Metabolism - eLS: Essential for Life Science

Flow chart of the metabolic pathway of tetrapyrrole biosynthesis towards the end products, chlorophyll and protohaem. Potential feedback control mechanisms in the metabolic pathway of tetrapyrroles are indicated. The synthesis of 5‐aminolaevulinate from glutamate is the rate‐limiting step of tetrapyrrole biosynthesis. Feedback regulation on the enzymes of the 5‐aminolevulinic acid pathway can start out from various sites: at the level of haem formation, at the level of protochlorophyllide reduction and at the beginning of the Mg‐porphyrin branch.

Effects of heavy metals and light levels on the biosynthesis of carotenoids and fatty acids in the macroalgae Gracilaria tenuistipitata (var
The two pathways of chlorophyll biosynthesis andchlorophyll catabolism in plants are located in distinct cellular compartments

Annual Review of Plant Physiology Vol

In our experiments, one-year-old Larix olgensis seedlings were cultivated in sand, and supplied with solutions with different concentrations of nitrate or phosphate. The effects of nitrogen and phosphorus supply on chlorophyll biosynthesis, total nitrogen content, and photosynthetic rate were studied. The experimental results are listed below: 1) 5-aminolevulinic acid (ALA) synthetic rate increased as nitrate concentrations supplied to larch seedlings increased from 1 to 8 mmol/L. But the rate decreased by 17% when nitrate concentration increased to 16 mmol/L, in contrast to the control. Under phosphate treatments, ALA synthetic rates were similar to those under nitrate treatments. The activities of porphobilinogen (PBG) synthase reached a maximum when larch seedlings were supplied with 8 mmol/L of nitrate or 1 mmol/L of phosphate. 2) when larch seedlings were supplied with 8 mmol/L of nitrate and 0.5 mmol/L of phosphate, the contents of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids reached a maximum. The total nitrogen contents in leaves increased as nitrate concentrations increased. 3) When phosphate concentrations increased from 0.125 to 1 mmol/L, the total nitrogen contents in leaves slightly increased; however, continuous increase of phosphate concentrations resulted in the decrease in total nitrogen contents in leaves. When nitrate concentrations increased from 1 to 8 mmol/L, soluble protein contents in leaves increased in general, and continuous increase of nitrate concentrations induced a decrease in soluble protein contents in leaves. Under treatment of 0.25 mmol/L of phosphate, the soluble protein contents reached a maximum. 4) In general, F v/F m increased as nitrate concentrations increased from 1 to 8 mmol/L, and continuous increase of nitrate concentration resulted in decrease in F v/F m. The similar changes occurred under phosphate treatments. As nitrate concentrations increased from 1 to 8 mmol/L, photosynthetic rates gradually increased, but when nitrate concentrations increased to 16 mmol/L, photosynthetic rate reduced by 16%, in contrast to the control. Photosynthetic rates reached a maximum when seedlings were supplied with 1 mmol/L, and an oversupply of phosphate (2 mmol/L) resulted in decrease in photosynthetic rates. The results suggested that supply levels of nitrogen affected ALA biosynthetic rates, activities of PBG synthase, and affected contents of chlorophyll and carotenoids. Moreover, nitrogen supply levels affected contents of total nitrogen and soluble proteins in leaves, and net photosynthetic rates. ALA biosynthesis rates and activities of PBG synthase were affected by phosphate supply, but contents of chlorophyll and carotenoids were not affected. And net photosynthetic rates were affected little by phosphate supply.

22/12/2010 · Effects of heavy metals and light levels on the biosynthesis of carotenoids and fatty acids in the macroalgae Gracilaria tenuistipitata (var

Photosynthesis Powerpoint Presentation

The pathway of chlorophyll catabolism. Chlorophyll is the central molecule that connects the biosynthetic and the catabolic pathway as well as the ‘chlorophyll cycle’. : ALA, 5‐aminolaevulinic acid; CAO, chlorophyll(ide) a oxygenase; CBR, chlorophyll(ide) b reductase; Chl, chlorophyll; Chlase, chlorophyllase; Chlide, chlorophyllide; CS, chlorophyll synthase; HCAR, 7‐hydroxymethyl chlorophyll(ide) a reductase; PAO, pheophorbide a oxygenase; pFCC, primary fluorescent chlorophyll catabolite; Pheide , pheophorbide ; Pchlide, protochlorophyllide; RCC, red chlorophyll catabolite; RCCR, RCC reductase.

Chlorophyll Biosynthesis in Bacteria: The Origins of Structural and Functional Diversity

Chlorophyll is located primarily in the mesophyll cells

Czarnecki O, Peter E and Grimm B (2011) Methods for analysis of photosynthetic pigments and steady‐state levels of intermediates of tetrapyrrole biosynthesis. Methods in Molecular Biology 775: 357–385.