A determination of the sub-units of arachin by osmometry. Arachins A, B and A1

Abstract

1. Osmotic pressure determinations of dissociated arachins are a particularly suitable method for determination of the number of sub-units in the protein, because they yield a number-average molecular weight. 2. Arachin, in 8m-urea-0.1m-sulphite, produces 12 sub-units from the form of molecular weight 345000. 3. When the urea concentration is varied the molecules became fully dissociated at 6m-urea-0.1m-sulphite. Although sulphite is necessary to break disulphide bridges, concentrations greater than 0.1m cause a re-aggregation of the sub-units. Similar results were obtained in guanidine solutions. 4. A new form of arachin has been discovered, A1, migrating more rapidly than arachin A. 5. The N-terminal residues of arachin have been re-investigated on more highly purified samples: they are glycine, valine and (iso)leucine in the proportions 4:1:1. 6. The three forms of arachin have the structure (B) beta(4)gammadelta, (A) alpha(2)beta(2)gammadelta and (A1) alpha(4)gammadelta, for the forms of molecular weight 170000. 7. Dissociation in 8m-urea produces some fragments, detected by gel electrophoresis, which appear to be dimers of the type alpha-S-S-beta, beta-S-S-beta, held together by disulphide bonds.

Gel electrophoretic analysis of peanut proteins and enzymes. I. Characterization of DEAE-cellulose separated fractions

“…As reported hy Dawson (19711, Tombs (1963, 1965, and Tombs and Lowe (1967), these data confirm that the peanut reserve proteins are primarily arachin and conarachin, which are themselves made up of smaller suhunits difficult to separate by the usual fractionation procedures. An attempt to further isolate and characterize the proteins within the conarachin and arachin fractions follows.…”

Optimization of arachin extraction from defatted peanut (Arachis hypogaea) cakes and effects of ultra-high pressure (UHP) treatment on physiochemical properties of arachin

“…Monterio and Prakash (1994) observed the subunit pattern of arachin to contain seven bands of molecular weights from 15,800 to 72,400 Da, but six of them were prominent. Tombs and Lowe (1967) also reported six major subunits and classified them into two groups of hydrophilic and hydrophobic subunits. It is known that proteins derived from different peanut species exhibit different behavior in the dissociation-association properties of the arachin molecular.…”

Studies on the effects of enzymatic hydrolysis on functional and physico-chemical properties of arachin

“…6). Tombs and Lowe (1967) observed the subunit pattern of arachin and reported that it contained six major subunits and classified them into two groups of hydrophilic and hydrophobic groups. Monteiro and Prakash (1994a, b) reported seven bands having molecular weights ranging from 158,000 to 72,400 Da and also showed that six prominent bands had molecular weights of 72,400, 60,300, 39,800, 33,100, 26,900 and 21,900 Da.…”