• The Korean Journal of Zoology
• /
• v.15 no.3
• /
• pp.101-104
• /
• 1972

A simple and economical method for separation of lactate and malate dehydrogenase isozymes is described in detail. The method is based on cellulose acetate strip electrophoretic separation of the isozymes, tetrazolium reduction to purple formazan. Resolution is as good as in the experiment using expensive equipments.

• The Korean Journal of Zoology
• /
• v.15 no.4
• /
• pp.193-205
• /
• 1972

Lactate and malate dehydrogenase isozymes in crude extracts of various tissues from 28 avian species were investigated by means of celluose acetate electrophoresis. In a given species the presence of two types of the malate dehydrogenase isozymes could be revealed in somatic tissues; one was characterized by fast electrophoretic mobility, and the other by slow mobility. Although the bird lactate dehydrogenase isozymes existed in a variety of species-specific molecular forms, they seemed to show the same pattern within the same genus and family.

• Toxicological Research
• /
• v.23 no.4
• /
• pp.289-299
• /
• 2007

Lipopolysaccharide (LPS) endotoxin is an active component in the outer membrane of Gram-negative bacteria. LPS is usually used as an inflammatory animal model. During the inflammation, diarrhea and changes in plasma proteins, in hepatic and/or intestinal microsomal cytochrome P450 (CYP) isozymes, and in the renal and/or biliary excretion of drugs have been reported. Thus, in rats pretreated with lipopolysaccharide endotoxin isolated from Klebsiella pneumoniae (KPLPS rats), the absorption, distribution, metabolism, and excretion of drugs could be expected to be altered. Interestingly time-dependent effects on the hepatic CYP isozymes have been reported in KPLPS rats. Thus, in KPLPS rats, the pharmacokinetics of drugs which are mainly metabolized via CYP isozymes could be expected to be time-dependent. In this review, an attempt to explain changes in pharmacokinetics of drug reported in the literature was made in terms of CYP isozyme changes or urinary and/or biliary excretion changes in KPLPS rats.

• Biomedical Science Letters
• /
• v.8 no.4
• /
• pp.203-209
• /
• 2002

Serum $\alpha$-D-mannosidase isozyme activities were measured in rats with ethanol intoxication combined with extrahepatic cholestasis induced by common bile duct ligation for the manifestation of the biochemical background of drinking hazards under the hepatobiliary disease. When chronic ethanol intoxication was combine with extraheparlc cholestasis, the activities of the rat's serum cytosolic, Iysosomal and Golgi $\alpha$-D-mannosidase isozymes increased at a more significant rate than those of the cholestasis alone. However, when acute ethanol intoxication was combined with extrahepatic cholestasis, the activities of the above isozymes were seen in the cholestasis alone. The results suggested that the elevated activities of these isozymes in chronic ethanol intoxication with cholestasis rather than in cholestasis alone were indications of increased hepatic damages, which caused these isozymes to leak into the blood in great quantity. Accordingly, the resulting data supported the fact that alcoholic drinks were enzymologically harmful to the hepatobiliary disease.

• BMB Reports
• /
• v.32 no.3
• /
• pp.299-305
• /
• 1999

Protein carboxyl O-methyltransferase (PCMT) catalyzes the transfer of a methyl group from Sadenosyl-L-methionine to free carboxyl groups of methyl-accepting substrate proteins. Two isozymes were separated by DEAE-Sephacel chromatography from porcine brain cytosol and designated PCMT I and II. Isozymes I and II were further purified by adenosyl homocysteine-Sepharose 4B and Superose HR 12 chromatography. The molecular weights of the purified PCMT I and II were determined by mass spectrometry to be 20,138 Da and 25,574 Da, respectively. The two enzymes displayed different isoelectric points; 7.9 for PCMT I and 5.3 for PCMT II. Isozymes I and II exhibited similar substrate specificities when tested with various methyl-accepting proteins. Myelin basic protein, a component of myelinated neurons, was found to be an excellent methyl-accepting substrate for both PCMT isozymes with different $K_m$ values, $21.1\;{\mu}M$ for PCMT I and $10.6\;{\mu}M$ for PCMT II. The PCMT activity and methyl-accepting capacity displayed similar distribution in the various brain regions with an exception of the lower values in the cerebellum. The overall distribution may relate to a general function of protein repair by PCMT in the brain.

• Korean Journal of Food Science and Technology
• /
• v.14 no.2
• /
• pp.125-129
• /
• 1982

Four peroxidase isozymes from horseradish roots (isozymes A, B, C and D) were isolated by chromatography and were thermally inactivated at $70{\sim}97^{\circ}C$ and pH 7.0. The four isozymes had different inactivation rates and the inactivation of each isozymes did not follow first order kinetics. D values of isozymes A, B, C, D and crude enzyme were 594s, 1850s, 2050s, 78s, 130s and z values were $24.0^{\circ}C$, $12.5^{\circ}C$, $18.0^{\circ}C$, $23.7^{\circ}C$ and $24.0^{\circ}C$, respectively. Sephadex gel chromatogram of the thermally treated isozyme C indicated that the shape and molecular weight of the native isozyme changed during inactivation.

• BMB Reports
• /
• v.41 no.6
• /
• pp.415-434
• /
• 2008

Phosphoinositide-specific phospholipase C is an effector molecule in the signal transduction process. It generates two second messengers, inositol-1,4,5-trisphosphate and diacylglycerol from phosphatidylinositol 4,5-bisphosphate. Currently, thirteen mammal PLC isozymes have been identified, and they are divided into six groups: PLC-$\beta$, -$\gamma$, -$\delta$, -$\varepsilon$, -$\zeta$ and -$\eta$. Sequence analysis studies demonstrated that each isozyme has more than one alternative splicing variant. PLC isozymes contain the X and Y domains that are responsible for catalytic activity. Several other domains including the PH domain, the C2 domain and EF hand motifs are involved in various biological functions of PLC isozymes as signaling proteins. The distribution of PLC isozymes is tissue and organ specific. Recent studies on isolated cells and knockout mice depleted of PLC isozymes have revealed their distinct phenotypes. Given the specificity in distribution and cellular localization, it is clear that each PLC isozyme bears a unique function in the modulation of physiological responses. In this review, we discuss the structural organization, enzymatic properties and molecular diversity of PLC splicing variants and study functional and physiological roles of each isozyme.

• Molecules and Cells
• /
• v.19 no.1
• /
• pp.97-103
• /
• 2005

The role of residue C323 in catalysis by human glutamate dehydrogenase isozymes (hGDH1 and hGDH2) was examined by substituting Arg, Gly, Leu, Met, or Tyr at C323 by cassette mutagenesis using synthetic human GDH isozyme genes. As a result, the $K_m$ of the enzyme for NADH and ${\alpha}-ketoglutarate$ increased up to 1.6-fold and 1.1-fold, respectively. It seems likely that C323 is not responsible for substrate-binding or coenzyme-binding. The efficiency ($k_{cat}/K_m$) of the mutant enzymes was only 11-14% of that of the wild-type isozymes, mainly due to a decrease in $k_{cat}$ values. There was a linear relationship between incorporation of [$^{14}C$]p-chloromercuribenzoic acid and loss of enzyme activity that extrapolated to a stoichiometry of one mol of [$^{14}C$] incorporated per mol of monomer for wild type hGDHs. No incorporation of [$^{14}C$]p-chloromercuribenzoic acid was observed with the C323 mutants. ADP and GTP had no effect on the binding of p-chloromercuribenzoic acid, suggesting that C323 is not directly involved in allosteric regulation. There were no differences between the two hGDH isozymes in sensitivities to mutagenesis at C323. Our results suggest that C323 plays an important role in catalysis by human GDH isozymes.

• Animal cells and systems
• /
• v.1 no.2
• /
• pp.389-394
• /
• 1997

We examined the effect of modulation of PKA isozymes on the growth of human ovarian cancer cells. Three ovarian cancer cell lines, 2774, SK-OV-3, and OVCAR-3, were examined in this study. The treatment of 5 uM 8-CI-cAMP, which has been known to down-regulate RI (or type 1 PKA) and up-regulate RII (or type II PKA), markedly inhibited the growth of all cell lines (50-80% at day 6). To test whether alteration in PKA regulatory subunits level can change the growth characteristics of ovarian cancer cells, we introduced RIIB- expression construct and Rla antisense-expression construct into 2774 cells. The overexpression of RIIB down-regulated Rla protein, and the antisense-expression of Rla up-regulated RIIB protein, showing that the intracellular levels of RI and RII are reciprocally regulated. In both cases, cell growth was reduced by 30% at day 2. These results indicate that the growth of ovarian cancer cells is controlled by the signals from PKA isozymes, and the modulation of PKA isozymes can be employed for the human ovarian cancer therapy.

• Journal of Nutrition and Health
• /
• v.4 no.1
• /
• pp.21-28
• /
• 1971

1. The effects of chloroform to the tissue lactic dehydrogenase (LDH) activities and its isozymes and to the tissue glutamic dehydrogenase (GDH) activities and its isoaymes are studied using the experimental albino male adult rats in this paper. The tissues studies are liver, kidney, heart, and brain. Besides the control group, two experimental groups are studied providing succeedingly 4 days interpariental administrations of chloroform, 0.0025ml and 0.025ml per day respectively. The changes of body weights, weights of organs, activities of GDH and LDH and their isozymes of each tissues, are analysed. 2. The body weights of rats are decreased due to the chloroform administration. 3. There are no significant differences of weights of organs due to the chloroform administration. 4. The significant decreases of tissue GDH activities and the significant changes in percent distribution of the GDH isozymes are found due to the chloroform administration. This weight be interpretated that chloroform effects to the protein and amino acid metabolism of rats. 5. Due to the chloroform administration, the significant changes in tissue LDH activities and in percent distribution of tissue LDH isozymes indicating the decreases of $LDH_1$ which is the aerobic heart type and the increase of $LDH_5$ which is the anaerobic muscle type, are observed. This could be estimated that chloroform effects to the carbohydrate metabolism, particularly to the anaerobic glycolysis of rats.