Figure 1.

SDS‐PAGE of purified rubber oxygenases. RoxA_{X sp} and RoxB_{X sp} were purified from filter‐concentrated supernatants of L‐rhamnose/LB‐medium‐grown ∆roxA Xanthomonas sp. 35Y cells with genome‐integrated rox A_{X sp} or rox B_{X sp} gene respectively. Lcp_K30 was purified from soluble French‐press extracts of L‐rhamnose/LB‐medium‐grown E. coli (p4782.1::strep‐lcp _K30) via Strep‐Tactin HC gravity flow affinity chromatography.

A. Purified proteins were separated by SDS‐PAGE and stained with silver. A molecular mass standard (M) with kDa values indicated is shown.

B. Oxidative cleavage of rubber. Poly(cis‐1,4‐isoprene) (100 < n < ≈ 10 000) is oxidatively cleaved by rubber oxygenases to oligo‐isoprenoids with terminal keto‐ and aldehyde groups. The methanol‐soluble products differ in the number of intact isoprene units (n) with 1 ≤ n < ≈ 12.