Investigation of purinelike compounds in immature maize kernels, germinating barley seeds, and yeast

Abstract

The purinelike compounds in immature maize kernels, germinating barley seeds, and baker's yeast were extracted with ethanol and separated by precipitation with cuprous oxide, chromatography on Dowex I and paper chromatography in n-butanol: acetic acid:water (4:1:5). The purines were located on the paper chromatograms with silver nitrate-bromophenol blue. The ultraviolet spectra of eluates in water and in 0.01 N NaOH were determined. The eluates were also examined for kinetinlike activity by testing their ability to retard the degradation of chlorophyll in the cells of leaf tissue. Nine purinelike compounds were detected in maize, ten in barley, and four in yeast. Guanosine, guanine, adenosine, and adenine were tentatively identified in maize; guanosine, guanine, adenosine, adenine, xanthine, and hypoxanthine in barley; and xanthine, hypoxanthine, and adenine in yeast. Other compounds that showed purinelike ultraviolet spectra could not be identified. The unknown purinelike compounds of R f values of 0.06, 0.75, and 0.81 from maize and 0.06 from barley retarded the breakdown of chlorophyll of wheat or barley leaves floated on their solution. All other compounds from maize, barley or yeast were inactive in this assay. It is suggested that several kinins occur naturally in plants. Since kinetin and naturally occurring kinins were effective in maintaining the detached green leaves turgid and green but were ineffective in preserving the turgidity of the detached albino leaves; therefore, chloroplast are in some way involved in the response of detached leaves to kinins.