Development of a high-throughput purification method and a continuous assay system for chlorophyllase

Kiani A.J. Arkus, Joseph M. Jez

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

In the degradation of chlorophyll, chlorophyllase catalyzes the initial hydrolysis of the phytol moiety from the pigment. Since chlorophyll degradation is a defining feature of plant senescence, compounds inhibiting chlorophyllase activity may delay senescence, thereby improving shelf life and appearance of plant products. Here we describe the development of a 96-well plate-based purification and assay system for measuring chlorophyllase activity. Integrated lysis and immobilized metal affinity chromatography plates were used for purifying recombinant hexahistidine-tagged Triticum aestivum (wheat) chlorophyllase from Escherichia coli. Chlorophyllase assays using chlorophyll as a substrate showed that the immobilized fusion protein displayed kinetic parameters similar to those of recombinant enzyme purified by affinity chromatography; however, the need to extract reaction products from a multiwell plate limits the value of this assay for high-throughput screening applications. Replacing chlorophyll with p-nitrophenyl-ester substrates eliminates the extraction step and allows for continuous measurement of chlorophyllase activity in a multiwell plate format. Determination of steady state kinetic constants, pH rate profile, the inhibitory effects of metal ions and esterase inhibitors, and the effect of functional group-modifying reagents validated the utility of the plate-based system. The combined purification and assay system provides a convenient and rapid method for the assessment of chlorophyllase activity.

Original languageEnglish
Pages (from-to)93-98
Number of pages6
JournalAnalytical Biochemistry
Volume353
Issue number1
DOIs
StatePublished - Jun 1 2006

Keywords

  • Chlorophyll
  • Chlorophyll degradation
  • Chlorophyllase
  • Hydrolase

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