In biochemistry, a metabolic pathway is a linked series of chemical reactions occurring within a cell. The reactants, products, and intermediates of an enzymatic reaction are known as metabolites, which are modified by a sequence of chemical reactions catalyzed by enzymes. (Wikipedia)
It is known that metabolism includes both catabolism (degradation of complex molecules) and anabolism (for synthesis of molecules). This brings me to my question. What kinds of non-metabolic pathways do exist?
I can only think of post-translational modifications and activation of gene expression by transcription factors. Can you give more examples?
I guess that you consider many signalling pathways to be pathways that are not metabolic?
e.g. Clotting cascade
Complement cascade
Phosphorylation relays
G-protein coupled receptor cascades (can involve diverse effects such as protein complexes forming and breaking, calcium influx, localisation)
Also, eukaryotic cells in particular show extremely complicated trafficking pathways that are metabolic in some cases, but are also used for control of cellular behaviour (e.g. controlled release vesicles containing some neuroactive signals at synapses).
Is this what you were thinking?
I guess that you consider many signalling pathways to be pathways that are not metabolic?
e.g. Clotting cascade
Complement cascade
Phosphorylation relays
G-protein coupled receptor cascades (can involve diverse effects such as protein complexes forming and breaking, calcium influx, localisation)
Also, eukaryotic cells in particular show extremely complicated trafficking pathways that are metabolic in some cases, but are also used for control of cellular behaviour (e.g. controlled release vesicles containing some neuroactive signals at synapses).
Is this what you were thinking?
I supposse you can include certain regulatory pathways as non metabolic ones. For example Specific protein 1(Sp1) is a regulatory transcription factor which may act as an enhancer of transcription promotion. There are many pathways that lead Sp1 to enter the nucleus and regulate the transcription of certain genes. Usually a promoter transcription factor is also necessary for Sp1 activity.
Dear Nicholas and Tomas,
Thank you for your answers.
I think signaling pathways are nice examples as non-metabolic pathways.
Even though, they could promote metabolic responses.
Best,
Arman
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