macroenzyme

macroenzyme

(1) Obsolete for aspartate aminotransferase (AST).
(2) A normal enzyme or isoenzyme complexed to an immunoglobulin resulting in persistent false elevation, which may trigger an aggressive and/or invasive workup to identify a nonexistent condition.
 
Examples
Macro-amylase, macro-AST, macro-CK, macro-LD; most common in those > age 60; identified by serum electrophoresis.
References in periodicals archive ?
A macroenzyme form of AST (macro-AST) was considered as the cause of the isolated AST increase.
We concluded that the patient had an immunoglobulin-AST complex macroenzyme and that no further testing or treatment was needed.
Although the clinical importance of macroenzymes is limited, the presence of a macroenzyme can be misleading in the interpretation of routine laboratory results (12), which can lead to a false conclusion of disease and to further expensive and dangerous investigations, or it can mask active disease (13).
Macroenzymes (3-5) are enzymes of high molecular mass that are formed in serum by self-polymerization or by association with other proteins.
Macroenzyme as a cause of unexplained elevation of aspartate aminotransferase.
He launched his own transformation while still in his twenties by identifying the first of a novel class of oversized proteins, the macroenzymes, which opened up a whole new field of study.
At the mitochondrial level, the synthesis and degradation of the macroenzymes of the electron transport system (ETS) is a function of the respiratory requirements of marine organisms (Owens & King 1975).
Just a few of the topics to be covered include HbA 1c, vitamin D, metabolic syndrome, sepsis, Alpha-1 antitrypsin deficiency, the CDC's lipid standardization program, macroenzymes, cystic fibrosis screening, lab disaster preparation, liquid chromatography, preeclampsia, closing the HIV window, islet autoantibody testing, hemoglobinopathies, value-based reimbursement, chronic kidney disease, assessing anlayte stability, LDTs, prostate specific antigen, biomarkers in Alzheimer's disease, and many more.
Macroamylase, macro creatine kinase, and other macroenzymes.
Our findings suggest the possibility that a modified molecule of cTnI (6) induced the immunocomplex formation, differently from most cases of macroenzymes described in the literature (7) in which a modified immunoglobulin molecule (IgG or IgA) was the responsible complexing factor that bound the normal protein.
His PhD thesis described and characterized the first case of "macro-amylasemia" and led to worldwide studies on macroenzymes.