PROTEIN COMPOSITION HAVING ISOPRENE POLYMERIZATION ACTIVITY AND USE THEREOF

The present invention provides a means for efficiently producing natural rubber and stably providing the same, and is aimed at stably providing a rubber resource. The present invention provides a protein composition that exhibits an isoprene polymerization activity and comprises a protein(s) (B) exhibiting the same activity as CPTL and either one of proteins (A-1) exhibiting the same activity as CPT6 and (A-2) exhibiting the same activity as CPT7, as well as a lipid membrane structure comprising the composition, a method for producing the same, a cell expressing a protein constituting the composition, a method for producing the same, and a method for producing an isoprene polymer compound using any of the above.