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Alfalfa Proteins: Isolation and Partial Characterization of the Major Component — Fraction I Protein
Author(s) -
HOOD L. L.,
CHENG S. G.,
KOCH U.,
BRUNNER J. R.
Publication year - 1981
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1981.tb04501.x
Subject(s) - fractionation , chemistry , sephadex , chromatography , polyacrylamide , polyacrylamide gel electrophoresis , medicago sativa , fraction (chemistry) , biochemistry , size exclusion chromatography , ammonium sulfate , biology , enzyme , botany , polymer chemistry
ABSTRACT Fraction I protein was extracted from fresh alfalfa ( Medicago sativa ) leaves and purified by ammonium sulfate fractionation, DEAE‐cellulose and Sephadex G‐200 chromatography. The isolate possessed a specific activity for ribulosebisphosphate carboxylase EC 4.1.1.39) of 1.01 units/mg protein. An approximate molecular weight of 573,000 was determined from values of S o 20,w (18.7) and D o 20,w (2.97). The protein contained 26 disulfide and 37 sulfhydryl groups—only one of which was titratable in the undenatured protein complex. It migrated as a single boundry by Tiselius electrophoresis and as a dense zone in polyacrylamide gels (disc). In the presence of SDS, two principal subunits of ∼52,000 and ∼12,500 daltons were revealed. Based on the FAO/WHO (1973) provisional pattern for essential amino acids, the protein was slightly deficient in sulfur‐containing residues.