Isoelectric focusing in immobilized pH gradients with carrier ampholytes added for high-resolution phenotyping of bovine beta-lactoglobulins: characterization of a new genetic variant.
The genetic variants of bovine beta-lactoglobulin (beta-lg) from the "Murnau-Werdenfelser" breed were analyzed in three different isoelectric focusing (IEF) systems. While carrier ampholyte IEF with a pH gradient of 0.2 pH/cm did not resolve the new variant W from the B variant and IEF in immobobilized pH gradients (IPG) with 0.1 pH/cm only partially resolved it, adequate separation was achieved with IPG-IEF in a pH 5.25-pH 5.7 gradient, in presence of 0.8 % w/v carrier ampholytes, both over a 10 and 17 cm separation distance. Apparent isoelectric points (pI's) and genetic frequencies (f) were as follows: beta-lg A, pI = 5.370, f = 0.364; beta-lg B, pI = 5.485, f = 0.480; beta-lg W, pI = 5.492, f = 0.076; and beta-lg D, pI = 5.610, f = 0.080. The small difference of delta pI = 0.007 between beta-lg B and beta-lg W respectively, seems to originate from a "silent" substitution of neutral amino acid residues as compared to the larger delta pI's of the other genetic variants of beta-lg, which result from substitution of charged amino acids.
Krause
I
I
Süddeutsche Versuchs- und Forschungsanstalt für Milchwirtschaft, Technische Universität München, Republic of Germany.
Buchberger
J
J
Weiss
G
G
Pflügler
M
M
Klostermeyer
H
H
D000818:Animals; D002417:Cattle / Q000235:genetics*; D004588:Electrophoresis, Cellulose Acetate / Q000379:methods; D005260:Female; D014644:Genetic Variation; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing / Q000379:methods; D007782:Lactoglobulins / Q000235:genetics* / Q000302:isolation & purification; D010641:Phenotype
D007782:Lactoglobulins