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Lipase present in the seeds of Jatropha curcasL. was isolated and some of its properties studied. Lipase activity was detected in both dormant and germinating seeds. The lipase was partially purified using a combination of ammonium sulfate precipitation and ultrafiltration, which increased the relative activity of the lipase by 28- and 80-fold, respectively. The lipase hydrolyzed palm kernel, coconut, and olive oils at comparable rates (approximately 5 µg FFA/µg protein/min); palm—Raphia hookeriand Jatropha curcasL.—oils at about twice the rate of the first group of oils; and palm and fish oils at a higher rate than all other oils. The lipase, however, had the highest activity with monoolein. Optimal pH and temperature for maximal lipase activity were 7.5 and 37°C, respectively. The addition of ferric ion (15 mM) to the lipase assay medium caused 90% inhibition of lipase activity, whereas calcium and magnesium ions enhanced lipase activity by 130 and 30%, respectively.

1An improved method for purifying hexose oxidase (d-hexose: O21-oxidoreductase, EC 1.1.3.5) from the marine red alga Chondrus crispusis described for obtaining enzyme suitable for structural characterization and use in bioconversion of lactose to lactobionic acid. This involved extracting enzyme from finely ground lyophilized tissue in sodium phosphate buffer (pH 7) containing 20% ammonium sulfate, eliminating the previously used solvent extraction and protease treatments, and by applying Poros perfusion chromatography media to achieve rapid separations of high resolution. Primary separation of contaminating phycobiliproteins and carrageenans was achieved using Poros DEAE-50. Sequential HPLC purification steps using Poros HP2 and Poros HQ were followed by Sephacryl S200 h chromatography. Enzyme activity was determined with a peroxidase-coupled assay using 2,2′-azino-bis (3-ethylbenzthiazoline-6 sulfonic acid) substrate. A final specific activity of 69 U/mg was obtained, representing a 100-fold purification with an activity recovery of about 10%. A native size of approximately 117,000 Da was determined by size exclusion chromatography, and SDS-PAGE revealed the presence of 38,000 and 29,000 Da polypeptides that appear to be derived from a 65,000 Da subunit. Further properties of the enzyme are described.

An enzyme from the alga Chlorella pyrenoidosa, previously identified as a hydroperoxide lyase (HPLS), cleaves the 13‐hydroperoxide derivatives of linoleic and linolenic acids into a volatile C5 fragment and a C13 oxo‐product, 13‐oxo‐9(Z),11(E)tridecadienoic acid (13‐OTA). Gas chromatography/mass spectrometry (GC/MS) headspace analysis of the volatile products indicated the formation of pentane when the substrate was the 13‐hydroperoxide derivative of linoleic acid, whereas a more complex mixture of hydrocarbons was formed when the 13‐hydroperoxide derivative of linolenic acid was the substrate. Analysis of the nonvolatile products by GC/MS and liquid chromatography/mass spectrometry (LC/MS) indicated the formation of 13‐OTA along with the 13‐ketone derivative. This enzymatic activity was inhibited by oxygen but was restored with nitrogen. The enzymatic cleavage activity was coincidental in purified fractions with lipoxygenase activity that produced the 13‐ and 9‐hydroperoxide derivatives of linolenic acid. The results suggest that the enzymatic cleavage activity in Chlorella pyrenoidosawas not a consequence of hydroperoxide lyase activity as previously thought, but was due to anaerobic lipoxygenase activity. This enzyme fraction was purified by (NH4)2SO4precipitation, gel filtration, and hydrophobic interaction chromatography. The purified enzyme has an approximate MW of 120 KDa and maximum activity at pH 8.0.