Isolation Of Alpha Research Articles

Lactic acid‐mediated isolation of alpha‐, beta‐ and kappa‐casein fractions by isoelectric precipitation coupled with cold extraction from defatted cow milk

The present study focused on the isolation of individual caseins (α, β and κ) from defatted cow's milk using lactic acid‐mediated isoelectric precipitation coupled with cold extraction technique, followed by purification using sucrose‐based density gradient centrifugation method. In vitro characterisation of the isolated casein fractions confirmed preservation of micellar morphology throughout the experimental conditions with anionic surface charge and wider particle size range. The RP‐HPLC analysis showed a peak at retention time of 25.13 min and 27.84 min for α‐casein and β‐casein, respectively. Results confirmed isolation of pure casein fractions from cow's milk which could serve as a rich source of bioactive peptides for nutraceutical/pharmaceutical applications.

Isolation of alpha and beta brain tubulin subunits after alkaline treatment of the protein.

We demonstrate here that brain purified tubulin can be dissociated into alpha and beta subunits at pH > 10 and that the subunits can be separated by using the Triton X-114 phase separation system. After phase partition at pH > 10, alpha tubulin but not beta tubulin behaves as a hydrophobic compound appearing in the detergent rich phase. After three extractions of the alkaline aqueous phase with Triton X-114, about 90% of the alpha tubulin was recovered in the detergent rich phase. The hydrophobic behavior observed for alpha tubulin after its dissociation at pH 11.5 was not due to an irreversible change of the protein, because when the detergent rich phase containing alpha tubulin was diluted with a buffer solution at pH 7.3 and the solution allowed to partition again, alpha-tubulin is recovered in the aqueous phase. The detergent in the aqueous phase of the alpha and beta tubulin preparations can be removed up to 90% by 12 h dialysis. The alpha and beta subunits of tubulin from kidney and liver behave, in this phase separation system, like those of brain tubulin.

Isolation of alpha, beta, and gamma conglycinins

Alpha, beta, and gamma conglycinins are soybean globulins which together with glycinin constitute the major components of the reserve proteins of soybean seeds ( Glycine max). These proteins were isolated by fractionation procedures based on Bio-Gel A-1.5m and Sephadex G-100 gel filtration, and DEAE-Sephadex chromatography. The isolated conglycinins were found to be homogeneous by immunoelectrophoresis in agar gel, disc electrophoresis, and disc immunoelectrophoresis. The antisera used for their identification were an anti-soybean water extract serum 123 and a monospecific anti-γ-conglycinin serum 130. In addition, a monospecific anti-glycinin serum 102 was used to detect possible contamination of conglycinin preparations by glycinin. The identity of α-conglycinin with a 2S soybean globulin component, β-conglycinin with the major component of a crude 7S soybean protein preparation, and γ-conglycinin with the major component of another crude 7S soybean protein preparation is discussed.