THE TOCOPHEROL,VITAMIN K,AND RELATED ISOPRENOID QUINONE COMPOSITION OF A UNICELLULAR RED ALGA (PORPHYRIDIUM CRUENTUM)1

The total lipids of axenically cultivated cells of Porphyridium cruentum were extracted with aqueous methanol-chloroform mixture and fractionated into neutral and polar lipids by silicic acid column chromatography. Thin-layer and reversed-phase paper chromatographic analyses of the neutral lipid fractions revealed the occurrence of plastoquinones (PQ) A and C, vitamin K₁ (K), ubiquinone-10 (Q₁₀), α-tocopherol (α-T), and α-tocopherolquinone (α-TQ) in the photoautotrophically cultured alga, and the same quinones but no tocopherol in the alga grown photoheterotrophically on glycerol. The plastoquinone A and vitamin K₁ were isolated, identified, and estimated by spectroscopic methods. The results indicated the following decreasing order of concentrations: autotrophic culture, PQ A > K > Q₁₀ > PQ C, α-TQ, α-T; heterotrophic culture, PQ A > Q₁₀ > K > PQ C, α-TQ. Except for the absence of plastoquinone B, the overall quinonoid composition was in general agreement with those previously reported for multicellular members of Rhodophyta, but the concentration level in total lipid was markedly lower.