Biochemical characterization of a dual enzymatic activity hydrolase from moss Physcomitrella patens

Karačić, Zrinka (2018) Biochemical characterization of a dual enzymatic activity hydrolase from moss Physcomitrella patens. Doctoral thesis, Sveučilište u Zagrebu, Prirodoslovno-matematički fakultet.

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Abstract

Nudix-dipeptidyl peptidase III is a plant enzyme with dual hydrolase activity: dipeptidylpeptidase III (DPP III) and phosphatase (Nudix). Homologues from moss (Physcomitrella patens) and angiosperm (Arabidopsis thaliana) were biochemically characterized. C-terminal domain of both homologues represents an atypical DPP III considering the active site (pentapeptide HEXXH instead of hexapeptide HEXXGH in typical DPPs III), and it is less active towards synthetic supstrates than typical, formerly characterized DPPs III. N-terminal domain is a member of Nudix superfamily. It was established that it has phosphatase activity towards isopentenyl-diphosphate and dimethylallyl-diphosphate, precursors in isoprenoid sythesis. Functional research on moss P. patens knock-out mutants showed that this enzyme is involved in cytokinin metabolism. Preliminary analysis of gene expression in the presence of stressors suggests that Nudix-DPP III enzyme is involved in plant response to stress (drought, salt and oxidative stress). Finally, the name isopentenyl diphosphate phosphohydrolase is suggested for the newly identified enzyme activity.

Item Type:

Thesis (Doctoral thesis)

Uncontrolled Keywords:

Nudix hydrolase; dipeptidyl-peptidase III; Physcomitrella patens; isopentenyl-diphosphate

Subjects:

NATURAL SCIENCES > Chemistry

Divisions:

Division of Organic Chemistry and Biochemistry

Projects: