Journal Article

Glyoxysomal Malate Dehydrogenase in Pumpkin: Cloning of a cDNA and Functional Analysis of Its Presequence

Akira Kato, Yoko Takeda-Yoshikawa, Makoto Hayashi, Maki Kondo, Ikuko Hara-Nishimura and Mikio Nishimura

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 39, issue 2, pages 186-195
Published in print February 1998 | ISSN: 0032-0781
Published online February 1998 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/oxfordjournals.pcp.a029356
Glyoxysomal Malate Dehydrogenase in Pumpkin: Cloning of a cDNA and Functional Analysis of Its Presequence

More Like This

Show all results sharing these subjects:

  • Biochemistry
  • Molecular and Cell Biology
  • Plant Sciences and Forestry

GO

Show Summary Details

Preview

Glyoxysomal malate dehydrogenase (gMDH) is an enzyme of the glyoxylate cycle that participates in degradation of storage oil. We have cloned a cDNA for gMDH from etiolated pumpkin cotyledons that encodes a polypep-tide consisting of 356 amino acid residues. The nucleotide and N-terminal amino acid sequences revealed that gMDH is synthesized as a precursor with an N-terminal extrapeptide. The N-terminal presequence of 36 amino acid residues contains two regions homologous to those of other micro-body proteins, which are also synthesized as large precursors. To investigate the functions of the N-terminal presequence of gMDH, we generated transgenic Arabidopsis that expressed a chimeric protein consisting of rβ-glucuroni-dase and the N-terminal region of gMDH. Immunologi-cal and immunocytochemical studies revealed that the chimeric protein was imported into microbodies such as gly-oxysomes and leaf peroxisomes and was then subsequently processed. Site-directed mutagenesis studies showed that the conserved amino acids in the N-terminal presequence, Arg-10 and His-17, function as recognition sites for the targeting to plant microbodies, and Cys-36 in the presequence is responsible for its processing. These results correspond to those from the analyses of glyoxysomal citrate synthase (gCS), which was also synthesized as a large precursor, suggesting that common mechanisms that can recognize the targeting or the processing of gMDH and gCS function in higher plant cells.

Keywords: rβ-Glucuronidase; Malate dehydrogenase (EC 1.1.1.37); Mircrobodies; Processing; Pumpkin (Cucurbita sp.); Targeting signal

Journal Article.  0 words. 

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.