Nature of nonenzymatically bound hexose in hemoglobin, albumin, and crystallin

• Published in: Biochemical medicine Vol. 34; no. 1; pp. 112 - 119
• Main Authors: Kumar, Anuradha, Sharma, K.Krishna, Pattabiraman, T.N.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.08.1985; Academic Press
• Subjects: Analytical, structural and metabolic biochemistry; Biological and medical sciences; Borohydrides; Crystallins - analysis; Fundamental and applied biological sciences. Psychology; Glucose - analysis; Glycated Hemoglobin A - analogs & derivatives; Glycated Hemoglobin A - analysis; Glycoproteins; Hexoses - analysis; Humans; Oxidation-Reduction; Protein Binding; Proteins; Serum Albumin - analysis; Proteins; Hexose; Crystallin; Molecular structure; Hemoglobin; Glycosylation; Serum albumin
• ISSN: 0006-2944; 1557-7996
• DOI: 10.1016/0006-2944(85)90068-7

Glucose incorporated in vitro during nonenzymatic glucosylation into albumin and hemoglobin was fully reducible by sodium borohydride unlike native albumin. Further, a prior hydrolysis under mild conditions (1 m oxalic acid:2 mHCl, 4 hr) was not required for in vitro incorporated glucose to yield maximal color intensity in the phenol-sulfuric acid reaction. Glucosyl-albumin, glucosyl-crystallin, and hemoglobin A 1 behaved similarly in this respect. Hexose bound to HbA 0 which alone showed an enhanced color intensity on prior acid hydrolysis was also not easily reduced by sodium borohydride. l-Cysteine (0.023 m) enhanced the color yield of glucosyl-hemoglobin, glucosyl-albumin, and glucosyl-crystallin to a lesser extent compared to fructose in the phenol-sulfuric acid reaction. Urea (6 m) also marginally increased the color intensity of glucosyl proteins and fructose.