Quantitation of Alcohol Dehydrogenase in Human Tissue and Serum by an Enzyme‐Linked Immunosorbent Assay (ELISA)

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Abstract
An enzyme‐linked immunosorbent assay for human alcohol dehydrogenase (AOH) has been developed. The method is based on preventing anti‐ADH antibodies from binding to ADH‐coated polystyrene microliter wells by preincubation with serial dilutions of ADH‐containing samples. The test detects ADH below 50 ng/ml. The sensitivity of the assay is superior to the commonly used photometric method and is particularly useful to quantitate ADH in crude tissue homogenates and in serum. Enzymatically active as well as inactive ADH can be detected, shown by the longer half‐life of the ADH antigenicity (6.5 months) as compared to the half‐life of the enzymatic activity (3.5 months). Approximately 10% of the total soluble protein in liver homogenates was ADH protein. The specific activity was around 0.4 lU/mg. It was higher in “atypical” livers although the absolute amount of ADH protein in these livers was identical with that in normal livers. ADH protein paralleled ADH activity in liver, stomach, and kidney homogenates. Normal serum on the average contained 59±16 ng/ml ADH (n = 9). Activity at these levels lies beyond the limits of spectrophotometric detectability. Serum of patients with liver disease exhibited elevated ADH levels paralleled by increased y‐glutamyl transpeptidase (GGT), glutamate oxalacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), but not alkaline phosphatase (AP) activities.