Resistance to methyl-parathion among Nebraska western corn rootworm, Diabrotica virgifera virgifera LeConte, populations is associated with increased hydrolytic metabolism of an organophosphate insecticide substrate. An electrophoretic method to identify resistant individuals based on the staining intensity of esterase isozymes on nondenaturing polyacrylamide gels was developed. Three groups of...

A histochemical method for distinguishing isozymes of myosin in rat ventricles has been developed. The procedure involves preincubation in pH 10.5, which inhibits Ca-activated ATPase of the V3 isozyme but not the V1 isozyme of myosin. The specificity of the technique has been demonstrated by comparison of results in hearts from young euthyroid and hypothyroid rats, in which the predominant isoz...

GST isozymes are an important part of the normal cellular defense against toxic xenobiotics and carcinogens. These multifunctional proteins can interact with a broad range of substrates in a variety of ways. In particular, GSTs have been implicated in the detoxication of many antineoplastic agents. Elevated levels of certain GST isozymes have been associated with malignant transformation and wi...

The previous studies of the interaction of purine analogs and human erythrocyte acid phosphatase isozymes were extended to include erythrocyte acid phosphatase from seven other species. Consistent responses, similar to the observations with the several genotypically different human isozymes, were observed. The isozyme from chimpanzee erythrocytes was similar to the human B-type isozyme while th...

Species and tissue-specific isozymes of phosphorylase display differences in regulatory properties consistent with their distinct roles in particular organisms and tissues. In this review, we compare crystallographic structures of regulated and unregulated phosphorylases, including maltodextrin phosphorylase (MalP) from Escherichia coli, glycogen phosphorylase from yeast, and mammalian isozymes...

We report the expression of the human muscle (CK-MM) and brain (CK-BB) creatine kinases in Escherichia coli. The proteins have been purified to apparent homogeneity and several of their physical and kinetic properties investigated. In the process, we have conclusively verified the correct DNA sequence of the genes encoding the respective isozymes, and determined the correct primary structure an...

Sphingosine kinase (SphK) is a lipid enzyme that maintains cellular lipid homeostasis. Two SphK isozymes, SphK1 and SphK2, are expressed from different chromosomes and several variant isoforms are expressed from each of the isozymes, allowing for the multi-faceted biological diversity of SphK activity. Historically, SphK1 is mainly associated with oncogenicity, however in reality, both SphK1 an...

The cysteine carboxypeptidase cathepsin X has been recognized as an important player in degenerative processes during normal aging and in pathological conditions. In this study we identify isozymes alpha- and gamma-enolases as targets for cathepsin X. Cathepsin X sequentially cleaves C-terminal amino acids of both isozymes, abolishing their neurotrophic activity. Neuronal cell survival and neur...