Calf intestinal alkaline phosphatase inhibition

Alkaline phosphatases [AP, orthophosphoric-monoester phosphorylase (alkaline optimum) EC 3.1.3.1] represent a large family of almost ubiquitous isoenzymes found in organisms from bacteria to animals. In mammals, there are two forms of AP, one form present in a variety of tissues and another form found only in the intestines. They share common attributes in that the phosphatase activity is optimal at pH 8-10, is activated by the presence of divalent cations, and is inhibited by cysteine, cyanides, arsenate, various metal chelators, and phosphate ions. Most conjugates created with AP utilize the form isolated from calf intestine. 

Different tissues contain different isoenzymes of alkaline phosphatase, and the intestinal isoenzyme is not inhibited by levamisole The enzyme used in immu-nohistochemistry is extracted from calf intestine, so that levamisole can be used as an inhibitor without affecting the desired reaction. For labile antigens in the intestine, it is better to switch to the peroxidase method. 

For the preparation of )3-D-glucopyranosyl (1 —> 4)-2-acetamido-2-deoxy- -D-glucopyranosyl-(l —> 0)-elymoclavine (11), the extension of previously prepared 2-acetamido-2-deoxy-)3-D-glucopyranosyl-(l —> 0)-elymoclavine (10) by the use of bovine -1,4-galactosyltranferase was chosen. Uridine 5 -di-phosphogalactose (UDP-Gal) served as a substrate, and alkaline phosphatase from calf intestine (EC 3.1.3.1) was used to remove feedback inhibition caused by the UDP produced [28]. 

M29. Morton, R. K., The substrate specificity and inhibition of alkaline phosphatase of cow s milk and calf intestinal mucosa. Biochem. J. 61, 232-240 (1955). 

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