Plant nucleotide-sugar pyrophosphatase/phosphodiesterase (nppase), method of obtaining same and use of same in the production of assay devices and in the production of transgenic plants

A method for obtaining an enzyme product of plant origin with nucleotide sugar pyrophosphatase/phospho-diesterase activity (NPPase) in its soluble isoform, having an amino acid sequence that contains at least one of the polypeptide fragments represented by SEQ ID NO:

• 1, SEQ ID NO:
• 2, SEQ ID NO:
• 3, SEQ ID NO:
• 4, SEQ ID NO:
• 5, SEQ ID NO:
• 6, SEQ ID NO:
• 7, SEQ ID NO:
• 8;
• SEQ ID NO:
• 9;
• SEQ ID NO:
• 10;
• SEQ ID NO:
• 11;
• SEQ ID NO:
• 12;
• SEQ ID NO:
• 13;
• SEQ ID NO:
• 14;
• SEQ ID NO:
• 15;
• SEQ ID NO:
• 16 and SEQ ID NO:
• 17, comprising the steps of:
• extracting an extract from the material of plant origin using a buffer, said extract comprising a protein fraction, filtering the extract purifying the extract by successive centrifugations and precipitations, with adjustments both of the pH and of the ionic strength of the medium, preferably including heating of the protein above 60° C. and cooling in ice, and purification by gel filtration, isoelectric focusing, denaturing-gel electrophoresis, or other equivalent means of purification of proteins extracted from plant tissues.

Use of a primers primer represented by SEQ ID NO:

• 18, SEQ ID NO:
• 19 or SEQ ID NO:
• 24 together with an mRNA from leaves of rice or barley for obtaining, by RT-PCR, a cDNA which, after being used as a probe on cDNA libraries of leaves of rice and barley, permits the isolation of cDNA's whose sequences are represented by SEQ ID NO:
• 20 and SEQ ID NO:
• 22, respectively.

Use of primers represented by SEQ ID NO:

• 18, SEQ ID NO:
• 19 or SEQ ID NO:
• 24 together with an mRNA from barley leaves for obtaining, by RT-PCR, a cDNA which, after being used as a probe on cDNA libraries of barley leaves, permits the isolation of cDNA whose sequence is represented by SEQ ID NO:
• 22.