BIOACTIVITY OF A PENTAPEPTIDE ISOLATED FROM CORN GLUTEN HYDROLYSATE ON LOLIUM-PERENNE L

Corn gluten hydrolysate (CGH) has been observed to inhibit root format ion of germinating grass seeds and has the potential for use as a natu ral herbicide. Five dipeptides have been isolated from the aqueous sol ution of CGH and proved to have greater root-inhibiting activity than the crude extract of CGH. The objective of this study was to isolate a nd identify other biologically active compounds from CGH with herbicid al properties. A perennial ryegrass (Lolium perenne L.) Petri dish bio assay was used to test for the bioactivity. A pentapeptide, Leu-Ser-Pr o-Ala-Gln, was isolated from CGH by using Sephadex G-15 gel filtration and two-step C18 reversed phase high performance liquid chromatograph y procedures. The compound suppressed growth of both the root and the shoot of germinating perennial ryegrass. It required 0.5 mg/mL of the pentapeptide to inhibit 50% of root length in the perennial ryegrass b ioassay, and this compound is more active than any of the five dipepti des isolated previously from CGH.