Some embodiments are directed to the use of creatine kinase or fragments thereof which induce analgesia, and also to the use of pharmaceutical compositions including the same, to relieve pain.

Provided is a method for producing circular DNA in which a region that is sandwiched by a region Ha and a region Hb in circular double-stranded DNA is substituted with the entirety or a portion of a linear-DNA fragment, wherein the region Hb is located downstream of the region Ha in the circular double-stranded DNA; the linear-DNA fragment is single-stranded or double-stranded linear DNA that has a homologous region that corresponds to the region Ha and a homologous region that corresponds to the region Hb, the latter homologous region being positioned downstream of the former homologous region; and the method comprising: preparing a reaction solution that contains the circular double-stranded DNA, the linear-DNA fragment, and a protein that has RecA-family-recombinase activity, and performing homologous recombination reaction by incubating the reaction solution for a predetermined period of time, thereby producing circular DNA in which the region that is from the region Ha to the region Hb in the circular double-stranded DNA is substituted with the region that is from the homologous region that corresponds to the region Ha to the homologous region that corresponds to the region Hb in the linear-DNA fragment.

A method of preserving a cell-free protein expression system includes preserving a cell extract with a first non-reducing sugar alcohol to provide a preserved cell extract, preserving a reaction buffer with a second non-reducing sugar alcohol to provide a preserved reaction buffer, and preserving an energy source, so that the cell extract, the reaction buffer, and the energy source are preserved separately.

A portable fluidic platform for rapid and flexible end-to-end production of recombinant protein biologics includes a bioreactor system hosting stable and robust cell-free translation systems that is fluidically integrated with modular protein separation functionalities (e.g., size exclusion, ion exchange or affinity chromatography systems) for purification of the cell-free expressed product and which are configurable for process-specific isolation of different proteins, as well as for formulation. The bioreactor utilizes lysates from engineered eukaryotic (e.g., yeast) or prokaryotic (e.g., bacterial) strains that contain factors for protein folding and posttranslational modifications. Combination of various purification modules on the same fluidic platform allows flexibility of re-routing for purification of different proteins depending on specific target requirements. Protein synthesis and purification modules are integrated into self-contained disposable fluidic cartridge that eliminates cross-contamination between runs. The platform allows for flexible production of protein biologics within 24 hours (from DNA to purified product).

Devices, kits, and methods for testing and monitoring creatine phosphokinase (CPK) in biological samples are provided.