Two isoforms of a nucleotide-sugar pyrophosphatase/phosphodiesterase from barley leaves (Hordeum vulgare L.) are distinct oligomers of HvGLP1, a germin-like protein

Two isoforms of ADPglucose pyrophosphatase/phosphodiesterase (AGPPase) have been characterized using barley leaves (Hordeum valgare L.). Whilst one of the isoforms: designated as soluble AGPPase1 (SAGPPase1), is soluble in lo w ionic strength buffers, the other, SAGPPase2, is extractable using cell w all hydrolytic enzymes or high salt concentration solutions, thus indicatin g that it is adventitiously bound to the cell wall, Both AGPPase isoforms a re highly resistant to SDS, this characteristic being utilized to purify th em to homogeneity after zymographic detection of AGPPase activity in SDS-co ntaining gets, N-terminal and internal amino acid sequencing analyses revea led that both SAGPPase1 and SAGPPase2 are distinct oligomers of the previou sly designated HvGLP1, which is a member of the ubiquitously. distributed g roup of proteins of unknown function designated as germin-like proteins (GL Ps). (C) 2001 Federation of European Biochemical Societies, Published by El sevier Science B.V. All rights reserved.