Structure of canine tracheobronchial mucin glycoprotein.
Canine tracheal mucin glycoprotein was isolated from beagle dogs fitted with tracheal pouches. Following exclusion chromatography on Sepharose CL-4B, noncovalently associated proteins were further resolved by dissociative density gradient centrifugation in CsBr-guanidinium chloride, and the mucin was then extracted with chloroform-methanol. The delipidated high-density product obtained had a nominal molecular weight of about 10(6) and an overall composition characteristic for a mucin glycoprotein, viz., a high content of serine and threonine, about 80% carbohydrate by weight, the absence of mannose or uronic acid, measurable ester sulfate, and a Pronase-resistant domain of molecular weight (1.75-3.0) X 10(5) which contains essentially all of the saccharide residues. Noncovalently bound lipid amounted to 6-10% by weight and was primarily cholesterol and cholesteryl esters. Cleavage of disulfide bonds by performic acid oxidation resulted in the release of a protein (Mr 65,000) not otherwise resolved by sodium dodecyl sulfate gel electrophoresis or the purification scheme.
Ringler
N J
NJ
Department of Biological Chemistry, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey 17033.
Selvakumar
R
R
Woodward
H D
HD
Simet
I M
IM
Bhavanandan
V P
VP
Davidson
E A
EA
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001980:Bronchi / Q000378:metabolism*; D002241:Carbohydrates / Q000032:analysis; D004285:Dogs; D008055:Lipids / Q000032:analysis; D008970:Molecular Weight; D009077:Mucins / Q000302:isolation & purification; D014132:Trachea / Q000378:metabolism*
D000596:Amino Acids; D002241:Carbohydrates; D008055:Lipids; D009077:Mucins