Abstract
With bovine serum albumin as the reference standard, the armadillo salivary-gland glycoprotein, although containing no chromogenic amino acids and only small amounts of colour-yielding peptides [Chou & Goldstein (1960) Biochem. J. 75, 100-115], is highly reactive in the Lowry phenol protein assay [Wu & Pigman (1977) Biochem. J. 161, 37-47]. After desialylation and Smith degradation of the glycoprotein, the Lowry phenol value increased by 13 and 30% respectively, which suggests that both sialic acid and N-acetylhexosamine exert shielding effects in this reaction. Acid hydrolysis for 30 min decreased the Lowry phenol value by more than 45%, which indicates that the peptide linkages and steric features affect the Lowry phenol reactivity. After hydrolysis for up to 6h, the remaining Lowry phenol value of the partially hydrolysed core protein paralleled the amount of unhydrolysed peptides, inferring that both acid-sensitive and acid-resistant chromophoric peptides are fairly evenly distributed along the whole polypeptide chain. As with bovine serum albumin, more than 80% of the colour yield obtained in the Lowry phenol assay with this glycoprotein is Cu2+-dependent.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- BOAS N. F. Method for the determination of hexosamines in tissues. J Biol Chem. 1953 Oct;204(2):553–563. [PubMed] [Google Scholar]
- Boursnell J. C., Hartree E. F., Briggs P. A. Studies of the bulbo-urethral (Cowper's)-gland mucin and seminal gel of the boar. Biochem J. 1970 May;117(5):981–988. doi: 10.1042/bj1170981. [DOI] [PMC free article] [PubMed] [Google Scholar]
- CHOU S. C., GOLDSTEIN A. Chromogenic groupings in the Lowry protein determination. Biochem J. 1960 Apr;75:109–115. doi: 10.1042/bj0750109. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dische Z., Danilchenko A. Modifications of two color reactions of hexoses with cysteine and sulfuric acid. Anal Biochem. 1967 Oct;21(1):119–124. doi: 10.1016/0003-2697(67)90090-5. [DOI] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Pamer T., Glass G. B., Horowitz M. I. Purification and characterization of sulfated glycoproteins and hyaluronidase-resistant mucopolysaccharides from dog gastric mucosa. Biochemistry. 1968 Nov;7(11):3821–3829. doi: 10.1021/bi00851a006. [DOI] [PubMed] [Google Scholar]
- SVENNERHOLM L. Quantitative estimation of sialic acids. II. A colorimetric resorcinol-hydrochloric acid method. Biochim Biophys Acta. 1957 Jun;24(3):604–611. doi: 10.1016/0006-3002(57)90254-8. [DOI] [PubMed] [Google Scholar]
- Wu A. M., Pigman W. Preparation and characterization of armadillo submandibular glycoproteins. Biochem J. 1977 Jan 1;161(1):37–47. doi: 10.1042/bj1610037. [DOI] [PMC free article] [PubMed] [Google Scholar]