title: The protein composition of the ocular zonules.
abstract: Bovine and human zonules were found to be composed of noncollagenous acidic glycoprotein with a high cysteine content, double that previously reported. In reduced zonular fractions the most prominent peptide had a molecular weight (MW) of approximately 70,000. Lesser quantities of 170,000, 50,000, and 35,000 dalton peptides were also present and a variable number of lower MW bands, depending upon the degree of reduction and denaturation. A fraction of bovine zonules soluble in low ionic strength buffers contained primarily a peptide of approximately 50,000 daltons, often present as a doublet. Amino acid and hexosamine content of these two fractions was consistent with the presence of at least two different glycoconjugates, one a proteoglycan. Carbohydrate analysis of whole zonules suggested that these glycoconjugates include a sialofucose-containing glycoprotein and a lesser quantity of xylose-containing proteoglycan. The amino acid profile and peptide content of the zonules resembled that of elastic tissue microfibrils, increasing further the possibility of a close relationship between these two fibrils.
mesh_terms: D000328:Adult; D000368:Aged; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D005123:Eye / Q000032:analysis* / Q000033:anatomy & histology; D005136:Eye Proteins / Q000032:analysis*; D006023:Glycoproteins / Q000032:analysis; D006801:Humans; D008875:Middle Aged
chemical_list: D000596:Amino Acids; D002241:Carbohydrates; D005136:Eye Proteins; D006023:Glycoproteins