Isoenzymes of alkaline phosphatase

Antithyroid drags have several side effects. The most frequent side effects are maculopapular rashes, pruritus, urticaria, fever, arthralgia and swelling of the joints. They occur in 1-5% of patients [1, 2]. Loss of scalp hair, gastrointestinal problems, elevations of bone isoenzyme of alkaline phosphatase and abnormalities of taste and smell are less common. The incidence of all these untoward reactions is similar with MMI and PTU. Side effects of MMI are dose-related, whereas those of PTU are less clearly related to dose [1]. PTU may cause slight transient increases of serum aminotransferase and y-glutamyl transpeptidase concentrations but also severe hq atotoxicity whereas methimazole or carbimazole can be associated with cholestasis. The side... 

Saleuddin, A. S. M. Isoenzymes of alkaline phosphatase in Anodonta grandis during shell regeneration. Malacologia 9, 501 (1969)... 

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. 

However, other isoenzymes of alkaline phosphatase are found in parts of the body such as bone, kidney, intestine and placenta, hence an isolated raised alkaline phosphatase may not be associated with liver dysfunction. In late pregnancy, alkaline phosphatase can increase to three times ULN, which may persist for several months after delivery, particularly if the mother is breastfeeding, owing to bone effects. In... 

EN113 Lee, K.N., Costello, R., Kroll, M. and Elin, R.J. (1992). Comparison of heat inactivation and electrophoresis for evaluating isoenzymes of alkaline phosphatase. Clin. Chem. 38, 984, Abstr. 209. 

Panteghini M, Pagani F. Reference intervals for two bone-derived enzyme activities in serum bone isoenzyme of alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TR-ACP). Clin Chem 1989 35 181-1. 

Anderson DJ, Branum EL, O Brien JF. Liver- and bone-derived isoenzymes of alkaline phosphatase in serum as determined by high-performance affinity chromatography. Clin Chem 1990 36 240-6. 

Also, before one can choose the substrate concentration for a particular method, the Michaelis constant must be determined. Usually, if the enzyme does not exhibit inhibition at high substrate concentration, it may be reasonable to use a working molar concentration of the substrate equal to 3 or 4 times the Km value so that the enzyme can manifest its highest activity. As in the case of j8-glucuronidase (F17), the conditions developed for a particular isoenzyme (of alkaline phosphatase) in one tissue may not be applicable for another isoenzyme in another tissue or for those present in serum. Hence reevaluation of every reaction condition (e.g., substrate concentration, optimum pH) is necessary for each isoenzyme. Vide infra 2.1.1. 

Information in the field of the isoenzymes of alkaline phosphatase may then be regarded as part of the evolving understanding of isoenzymes in general, which at the present time is rather confused with respect to its biological and clinical significance. 

H15a. Hodson, A. E., Latner, A. L., and Raine, L. Isoenzymes of alkaline phosphatase. 

Nl. Nathanson, L., and Fishman, W. H., New observations on the Regan isoenzyme of alkaline phosphatase in cancer patients. Cancer 27, 1388-1397 (1971). 

Isoenzymes are forms of an enzyme which are structurally different but have similar catalytic properties. Measurement of the isoenzymes of alkaline phosphatase and creatine kinase are of clinical value. 

The activity of the enzyme alkaline phosphatase has traditionally been used as an indicator of bone turnover. The osteoblasts which lay down the collagen framework and the mineral matrix of bone have high activity of this enzyme. Increased osteoblastic activity is seen as an elevated alkaline phosphatase activity in a scnim specimen. Indeed, children who have active bone growth compared with adults have higher normal alktiline phosphatase activity iti semm. However alkaline phosphatase is also produced by the ceils lining the bilecanaliculi and is a marker for cholestasis. The botie isoenzyme of alkaline phosphatase may be measured, but there is need for a more specific and more sensitive marker. 

Dorner, J. L., W. R. Hoffmann, and G. B. Long. 1974. Corticosteroid induction of an isoenzyme of alkaline phosphatase in the dog. American Journal of Veterinary Research 35 1457-1458. 

Vallee, 1969 Schlesinger et al., 1969) and on the nature of organ-specific isoenzymes of alkaline phosphatase (Moss, 1969 Fishman, 1969 Fishman and Ghosh, 1967). 

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