cDNA cloning and characterisation of an alpha-glucosidase gene from potato (Solanum tuberosum L.).
Using an Arabidopsis thaliana expressed sequence tag with sequence similarity to human lysosomal alpha-glucosidase as a probe, a potato cDNA was isolated. The cDNA encodes a polypeptide with an Mr value of 105,400 and the most significant matches of the deduced amino acid sequence are with members of family 31 of glucosyl transferase. The potato cDNA was expressed in a strain of Saccharomyces cerevisiae that is deficient in maltase activity and unable to grow using maltose as a carbon source (ABYSMAL81). Expression of the potato cDNA in the mutant yeast strain restores its ability to use maltose as a carbon source for growth. Additionally, alpha-glucosidase activity could be measured in extracts of the yeast cells following complementation. A range of maltodextrins were substrates for this activity. The steady-state expression level of the potato alpha-glucosidase gene was low in most tissues examined, the highest levels occurring in sprouting tubers and source leaves.
Unit of Plant Biochemistry, Scottish Crop Research Institute, Invergowrie, Dundee, UK. cepmt@scri.sari.ac.uk
M A
MA
Taylor
L A
LA
George
H A
HA
Ross
H V
HV
Davies
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D018744:DNA, Plant / Q000235:genetics*; D015870:Gene Expression; D005816:Genetic Complementation Test; D006801:Humans; D008320:Maltose / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D011198:Solanum tuberosum / Q000201:enzymology* / Q000235:genetics*; D000520:alpha-Glucosidases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D018076:DNA, Complementary; D018744:DNA, Plant; D008320:Maltose; D000520:alpha-Glucosidases