Characterization of diphosphonucleotide phosphatase/phosphodiesterase fromyellow lupin (Lupinus luteus) seeds

A phosphatase cleaving the pyrophosphate bond in diphosphonucleotides and p hosphodiester bond in various phosphodiesters (pH optimum at 6.25) was puri fied from yellow lupin (Lupinus luteus L.) seeds. The enzyme is 75 kDa mono meric glycoprotein (pI=6.4) with 4.4% of carbohydrate (mannose, N-acetylglu cosamine, fucose and xylose). Analysis of its partial amino acid sequence ( 8 peptides, 101 amino acid residues) together with no divalent cation requi rements for catalysis points out that the purified enzyme is different from known plant pyrophosphate cleaving enzymes (apyrases and inorganic pyropho sphatases). Its physiological role could be related to a regulation of diph osphonucleotides level in plant metabolism. (C) 2000 Elsevier Science B.V. All rights reserved.