Through ongoing joint research with Professor Yuzuru Tozawa of Saitama University, Associate Professor Seiji Takahashi of Tohoku University and Associate Professor Satoshi Yamashita of Kanazawa University, Sumitomo Rubber Industries has invented a new technique to evaluate enzymes using artificial membranes (nanodiscs). The technique will be used to gather further information on the mechanisms behind the biosynthesis of natural rubber.
With previous evaluation techniques making use of natural membranes, the latest technique from Sumitomo Rubber and its joint researchers utilizes artificial membranes to eliminate environmental impurities. As a result, higher precision evaluations will be enabled.
By using the technique to discover new significant constituents of natural rubber, all of the parties involved believe rubber yields can be improved, in addition to other advancements such as the potential for laboratory biosynthesis of natural rubber.
Three specific proteins play an important role in natural rubber biosynthesis (the synthesis of long polyisoprene chains) in Pará rubber trees: Hevea Rubber Transferase 1 (HRT1), HRT1-REF Bridging Protein (HRBP) and Rubber Elongation Factor (REF).
Parties involved state that it was not clear under what conditions HRT1 (an enzyme believed to bind multiple molecules together) fulfilled its particular function. Previously, HRT1 has been observed synthesizing isoprene chains when placed on natural membranes, such as those formed by rubber particles or yeast. However, the use of natural membranes presented an issue; that impurities in the membranes would inevitably contaminate the test environment, making it impossible to identify the other constituents necessary for isoprene chain synthesis. Because of this, the new enzyme evaluation technique was developed to use artificial membranes (nanodiscs) which contain no natural materials.
When using the latest technique Sumitomo Rubber discovered that HRT1 synthesizes isoprene chains when both HRT1 and HRBP are present on one of these artificial membranes. This occurrence marked the first time that HRT1 has been observed performing this function on an artificial membrane.