Immunochemical features in the classification of human alcohol dehydrogenase family.

Human alcohol dehydrogenase (ADH) constitutes a complex family with diversified functions. Rabbit antihuman class I, II, III, and IV ADH antisera were prepared and used as probes to compare cross-reactivity with the isozymes across classes by serniquantitative Western blotting and quantitative enzyme-linked immunosorbent assay (ELISA). The interclass cross-reactivities with the noncognate isozymes by ELISA, generally similar to 0-35%, appeared considerably lower than those of the intraclass cross-reactivities except with the class IV isozyme. The anti-ADH1B1, ADH1C1, and ADH3 antisera, but not the anti-ADH2, exhibited similar to 80% cross-reactivity with ADH4. The intraclass cross-reactivities among class I isozymes ADH1A, ADH1B1, and ADH1C1 with anti-ADH1B1 or anti-ADH1C1 antisera were similar to 90%. Immunohistochemistry detecting with class-specific antibodies for ADH1-4 isolated from the corresponding antisera demonstrated that ADH4 was the predominant isoform expressed in the basal and suprabasal layer of human esophagus mucosa, whereas it was virtually devoid in the adjacent squamous cell carcinoma. Thus, the setup is more valuable for scanning ADH expression at protein level in different tissues and under different conditions, and maybe not as a tool for classification. (c) 2006 Elsevier Inc. All rights reserved.