ISSN:
1573-4927
Keywords:
Riboflavin-binding protein
;
mutant protein
;
heterozygote
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract A genetic defect, avian riboflavinuria, was discovered in a strain of Single Comb White Leghorn chickens and has been attributed to the absence of functional riboflavin-binding protein (RBP). The ratio of functional RBP in blood, egg yolk, and egg white was 2 (RdRd): 1 (Rdrd): 0 (rdrd). The present study on non-riboflavin-binding, cross-reacting proteins (CRPs) from RdRd, Rdrd, and rdrd hens involved partial purification and immunochemical quantitation using antiserum to RBP. Immunoreactivities (µg/g liver) of CRPs were found to be 2.6 (RdRd): 1.3 (Rdrd): 0.02 (rdrd). Reciprocal cross-reactions were observed with rabbit sera directed toward both RdRd CRP and RBP. Reaction of the CRPs with antiglycopeptide serum (specific for β-linked galactose) showed that they were glycosylated. CRPs from RdRd and Rdrd hens had relative antigenicities similar to that of RBP (K rel ⋍ 1), while rdrd CRP had a significantly lower antigenicity (K rel=0.003). The molecular weights of the CRPs as determined by SDS-polyacrylamide gel electrophoresis were as follows: RdRd=31,600, Rdrd=30,900, and rdrd=27,500. The molecular weight of egg yolk RBP was 34,700 by the same method. The conclusion is drawn that the rd gene codes for a nonfunctional mutant protein, possibly an “altered precursor,” that is different from RBP.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00484343
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