What is the maximum length of peptide which considered to be hard for synthesis by the current technology?

I am a molecular biologist and work with recombinant proteins. I am wondering what the cut point, in terms of length, is at which I should produce the peptide using heterologous expression rather than ordering a peptide synthesis service? What is the maximum length which makes it hard to chemically synthesis the peptide? Any ideas are welcome.




The protein lysozyme (160 amino acids) has been synthesized using a flow reactor according to <https://www.chemistryworld.com/news/protein-synthesis-revolution-on-way-as-large-peptides-made-in-hours-not-days/4011891.article> . The same article suggest 50 amino acids as a cut-off where the traditional solid state synthesis would be infeasible.


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