Gene frequencies of the enzymes ALADH, GOT2, GPT, PGM3, SAHH and UMPK in a Swiss population

The polymorphisms of the enzymes ALADH, GOT2, GPT, PGM3, SAHH, and UMPK have been studied in a population of Northern Switzerland (Zürich). The results are compared with those of other European populations.     

Genetic polymorphism of GPT and GLO-I in Galicia (northwest Spain): a comparative study

GPT and GLO-I phenotypes were determined by means of isoelectric focusing and starch gel electrophoresis, respectively, in a sample of the Galician population (Northwest Spain); GPT: n = 302, GLO-I: n = 500. The gene frequencies come to: GPT1 = 0.5099, GPT2 = 0.4901; GLO1 = 0.4930, GLO2 = 0.5070. No rare variants were found. The Galician gene frequencies are compared with those obtained on other populations from different parts of the world.     

Comparative studies on the human glutamate-pyruvate transaminase phenotypes--GPT 1, GPT 2-1, GPT 2.

The quantitative differences between the activity of the 3 common phenotypes of human red cell GPT has been confirmed. In addition, the activity of red cell GPT 1 was found to be greater in young children than in adults. No such difference was found for the GPT 2 phenotype. The activity of the red cell GPT 1 was found to decrease with age, reaching the adult level at the age of 10 to 12 years. Red cell GPT of all the 3 common phenotypes in both adults and children was found to show a similar response to the addition of excess pyridoxal phosphate. A method has been devised for the partial purification of human GPT (cytoplasmic) from liver. GPT 1 and GPT 2 have been purified, and very few significant differences were found amongst the physical and kinetic parameters tested.     

中国内蒙古鄂伦春、鄂温克、达斡尔族人五种酶型和二种血清型遗传多样性分析

应用G6PD ACP ADA AK1和GC-Tf同步电泳的方法及GPT凝胶电泳的方法,分别对内蒙古境内鄂温克、鄂伦春、达斡尔族人476份血痕红细胞酶型:GPT、6-PGD、ACP、ADA、AK1和血清型GC、Tf的遗传多样性进行检测。根据所测表型频率分布、计算出基因频率分布,识别能力和累积识别能力,就其多态性特征及其在法医学鉴定中的应用价值进行了分析讨论。同国内外不同资料进行了比较研究,阐明了三群体上述酶型和血清型遗传多样性分布的规律和特点。从血型遗传学角度探讨了鄂伦春、鄂温克、达斡尔族间的族源、血缘关系。被调查人群中未发现各酶型和血清型的变异型。     

Use of recombinant retroviruses to study the regulation of integrated adenovirus early promoters.

Adenovirus E1A gene products are capable of modulating the expression of a variety of integrated genes. To study the mechanisms by which this regulation occurs, recombinant retroviruses have been utilized to establish cell lines containing an integrated copy of either the adenovirus E2 or E3 promoter adjacent to the bacterial guanine phosphoribosyl transferase (GPT) gene. These cell lines have been characterized with respect to both basal and E1A-induced levels of GPT gene expression. Cell lines with low levels of GPT gene expression showed increased expression in the presence of E1A, whereas cell lines with high basal levels of GPT gene expression had decreased GPT RNA levels in the presence of E1A. Further characterization of these cell lines revealed E1A modulation of the accumulation of RNA initiating at a retrovirus promoter adjacent to the E2 or E3 promoter. The use of the GPT gene as a marker of E2 or E3 promoter activity has allowed the isolation of cell lines which have spontaneously increased their levels of GPT RNA. A preliminary characterization of four of these cell lines has indicated that GPT gene expression is increased as a result of cis activation of the E2 promoter.     

Red cell glutamic-pyruvic transaminase polymorphism in a sample of the Italian population a new variant allele: GPT8.

247 individuals from Northern Italy have been tested for red cell glutamic-pyruvic transaminase (GPT) polymorphism. An abnormal phenotype has been detected. Family data support the hypothesis of the existence of a new variant allele, GPT8, at the GPT locus.     

Absence of red cell glutamic-pyruvate transaminase: discovery of a "silent" allele homozygote.

An individual with complete absence of red blood cell glutamic-pyruvate transaminase (GPT) activity has been discovered in a South African family of Lebanese origin. The subject, who also shows a low level of serum GPT, appears to be perfectly healthy. His children, all obligatory heterozygotes for the GPT0 allele, have lower than average levels of the red cell enzyme. An apparent instance of anomalous segregation of red cell GPT resulting from the inheritance of the GPT0 allele was recorded in one of the proband''s grandchildren.     

Two previously undetected variants of glutamic-pyruvic transaminase found by acidic polyacrylamide gel electrophoresis.

Two new electrophoretic variants of glutamic-pyruvic transaminase (GPT) have been found by polyacrylamide gel electrophoresis at acidic pH. They appeared to represent a single allele, GPT 2, by the standard method of starch gel electrophoresis. Studies in families show that they are inherited as codominant alleles at the GPT locus. Population frequencies are about the same as those of other rare GPT variants. Their behavior on gels is consistent with both of them having substitutions of histidines in place of uncharged amino acids.     

Studies on glutamic-oxalacetic (GOT) and glutamic-pyruvic (GPT) transaminases of swine kidney worm Stephanurus dentatus (Diesing, 1839). I. Assay and general properties.

Biochemical studies on the two transaminases GOT and GPT of swine kidney worm Stephanurus dentatus have been made. GOT has been found much more active than GPT. Enzyme activities are based on the formation of oxaloacetate (GOT) or pyruvate (GPT) from aspartic acid and alanine respectively with oxoglutarate. A linear relationship is observed between the enzyme concentration and activity. GOT shows a maximum activity at pH 8.0 and Michaelis constant 9 X 10(-3) M for male and 2.9 X 10(-3) M for female. GPT has an optimum pH of 7.5 and a Michaelis constant 19 X 10(-3) M for male and 8 X 10(-3) M for female. The optimum temperature for both GOT and GPT was 60 degrees C.     

Distribution of GPT types in Norway.

GPT phenotype determinations were performed in 4,148 unrelated Norwegians. The frequencies of the two common alleles were Gpt1 = 0.537 and Gpt2 = 0.461. A total of 13 individuals showed the phenotypic expression of 3 rare GPT alleles, Gpt3, Gpt6, and Gpt7. No heterogeneity in phenotype distribution was found, neither in the two sexes nor regionally in Norway. 97 foreigners involved in paternity cases in Norway showed a phenotype distribution not differing from that of Norwegians. In two small additional samples of Ethiopians and Easter Islanders, Gpt1 frequencies were 0.737 and 0.531, respectively. There were significant differences in phenotype distribution between NOrwegians and all African populations tested, some of the Asiatic population, Lapps and a few other populations.     

Glutamic-pyruvic transaminase (GPT) in non-human primates,I. Its activities and electrophoretic variation in red blood cells

Glutamic-pyruvic transaminase (GPT) in red cells of 25 species of non-human primates was investigated. There were significant differences in red cell GPT activities among species. Some species in the Prosimiae and the Ceboidea have high red cell GPT activities, while the others of these families examined have low activities. In contrast, red cell GPT activities were too low to be detected in the Cercopithecoidea and the Pongidea. The intraspecific variation of GPT zymograms was observed in Aotes trivirgatus by starch gel electrophoresis.     

Seed dispersal potential of Asian elephants

Elephants, the largest terrestrial mega-herbivores, play an important ecological role in maintaining forest ecosystem diversity. While several plant species strongly rely on African elephants (Loxodonta africana; L. cyclotis) as seed dispersers, little is known about the dispersal potential of Asian elephants (Elephas maximus). We examined the effects of elephant fruit consumption on potential seed dispersal using the example of a tree species with mega-faunal characteristics, Dillenia indica L., in Thailand. We conducted feeding trials with Asian elephants to quantify seed survival and gut passage times (GPT). In total, 1200 ingested and non-ingested control seeds were planted in soil and in elephant dung to quantify differences in germination rates in terms of GPT and dung treatment. We used survival analysis as a novel approach to account for the right-censored nature of the data obtained from germination experiments. The average seed survival rate was 79% and the mean GPT was 35 h. The minimum and maximum GPT were 20 h and 72 h, respectively. Ingested seeds were significantly more likely to germinate and to do so earlier than non-ingested control seeds (P = 0.0002). Seeds with the longest GPT displayed the highest germination success over time. Unexpectedly, seeds planted with dung had longer germination times than those planted without. We conclude that D. indica does not solely depend on but benefits from dispersal by elephants. The declining numbers of these mega-faunal seed dispersers might, therefore, have long-term negative consequences for the recruitment and dispersal dynamics of populations of certain tree species.     

cDNA cloning, genomic structure, chromosomal mapping, and functional expression of a novel human alanine aminotransferase

Alanine aminotransferase (ALT) catalyzes the reversible transamination between alanine and 2-oxoglutarate to form pyruvate and glutamate, and thereby has a key role in the intermediary metabolism of glucose and amino acids. Two ALT isoenzymes are known to exist, but only one ALT gene has been cloned, GPT. In this study, we cloned a homolog of GPT and named it GPT2, and the corresponding protein ALT2. GPT2 shares 69% identity and 78% similarity at the protein level to the previously cloned GPT. The human gene GPT2 encodes a 3.9-kb mRNA, consists of 12 exons, spanning approximately 50 kb of the genome, and maps to chromosome 16q12.1. GPT2 and GPT differ in mRNA expression in that GPT2 is highly expressed in muscle, fat, and kidney, whereas GPT is mainly expressed in kidney, liver, and heart. In addition, GPT2 seems to be the predominant form of GPT at the mRNA level in these tissues. Expression of ALT2 protein in Escherichia coli produced a functional recombinant enzyme that catalyzes alanine transamination, confirming that the enzyme is an ALT. The more abundant expression of GPT2 than GPT, especially in muscle and fat, suggests a unique and previously unrecognized role of this gene product in glucose, amino acid, and fatty acid metabolism and homeostasis.     

Enzymatic degradation protects neurons from glutamate excitotoxicity

Several enzymes with the capacity to degrade glutamate have been suggested as possible neuroprotectants. We initially evaluated the kinetic properties of glutamate pyruvate transaminase (GPT; also known as alanine aminotransferase), glutamine synthetase, and glutamate dehydrogenase under physiologic conditions to degrade neurotoxic concentrations of glutamate. Although all three enzymes initially degraded glutamate rapidly, only GPT was able to reduce toxic (500 microM) levels of glutamate into the physiologic (<20 microM) range. Primary cultures of fetal murine cortical neurons were subjected to paradigms of either exogenous or endogenous glutamate toxicity to evaluate the neuroprotective value of GPT. Neuronal survival after exposure to added glutamate ranging from 100 to 500 microM was improved significantly in the presence of GPT (> or =1 U/ml). Cultures were also exposed to the glutamate transporter inhibitor L-trans-pyrrolidine-2,4-dicarboxylate (PDC), which produces neuronal injury by elevating extracellular glutamate. GPT significantly reduced the toxicity of PDC. This reduction was associated with a reduction in the PDC-dependent rise in the medium concentration of glutamate. These results suggest that enzymatic degradation of glutamate by GPT can be an alternative to glutamate receptor blockade as a strategy to protect neurons from excitotoxic injury.     

Hepatic and renal changes in albino rats caused by the administration of chromium (VI) in drinking water

The effects of sodium chromate administered in drinking water on liver and kidney of albino rats have been studied, through investigation of histological alterations and monitoring changes on serum urea levels and transaminases (GOT and GPT). Measurements have been done after 4, 8 and 12 weeks of treatment. The liquid intake of treated animals decreases with time. The amount of water drunk by treated rats is 1/2 of that drink by controls after 12 weeks. The histological alterations in liver and kidney are similar to those described elsewhere. Serum urea level is always higher in treated animals than in controls. GOT levels are similar in both treated and control rats, although always higher in the treated ones. GPT levels increase significantly after 12 weeks of treatment.     

Evidence that the hamster tunicamycin resistance gene encodes UDP-GlcNAc:dolichol phosphate N-acetylglucosamine-1-phosphate transferase.

A cDNA clone isolated from Chinese hamster ovary cells conferred elevated GlcNAc-1-P-transferase (GPT) activity and resistance to tunicamycin in transfected cells (Zhu, X., and Lehrman, M. A. (1990) J. Biol. Chem. 265, 14250-14255). It had been assumed that this cDNA, termed TRG for tunicamycin resistance gene, encoded GPT enzyme. However, other functions were not ruled out. Thus, by one of several mechanisms, the TRG protein could have instead functioned by activation of the transfected host's endogenous GPT enzyme. To analyze the biochemical function of the TRG protein, hamster TRG cDNA was stably expressed at high levels in Chinese hamster ovary cells. In addition, several antipeptide polyclonal antibodies directed against the predicted TRG protein were obtained. With these tools in hand, experiments were performed to test the hypothesis that the TRG encodes GPT enzyme, as well as to rule out other possible functions for the TRG protein. These experiments included examination of the effects of solubilization of membranes on TRG-dependent GPT activity, the apparent binding of tunicamycin to the TRG protein, and the immunoadsorption of GPT activity with TRG protein-specific antibodies. From these results, we conclude that the hamster TRG most likely encodes GPT enzyme.     

Population genetic studies in the Kimberley of Western Australia

More than 800 blood samples from members of 13 tribal groups in the northwest of Australia have been tested for 18 enzyme systems controlled by 21 loci and for haemoglobin. Two novel alleles, PGM2(11) and ACP1F, are each restricted to a single tribal population, suggesting relatively recent mutations. Other alleles conform very broadly with their distributions in other Australian Aboriginal populations. In particular, PGM2(3) maintains its inland distribution whilst PGDE and PEP B6 continue to be restricted to the north of the continent. Comparisons between tribes show the Baada to be distinctive, with high values of PGM1(2), GPT2, CA2(4) and ESD2 as well as having the novel allele ACP1F.     

Genetic studies in Saudi Arabia: red cell enzyme, haemoglobin and serum protein polymorphisms.

Population genetic studies in Saudi Arabia are performed for EsD, GPT, AcP, ADA, AK, 6-PGD, PGM, C3, Tf, Hp, Gc, Pi, Bf, Hb, ABO-blood groups and Rh-factor, level of the third component of complement and immunoglobulins. The data are compared with reported frequencies in European and African populations.     

Effect of some--SH and other reagents on aspartate aminotransferase and L-alanine aminotransferase of Paramphistomum explanatum Fischoeder, 1901.

Studies on aspartate aminotransferase (GOT) and L-alanine aminotransferase (GPT) of Paramphistomum explanatum have shown that GPT activity has more than twice the activity of GOT. The effect os some--SH reagents like cadmium, mercury, silver and iodoacetamide revealed that both enzymes were inhibited except that GOT was insensitive to cadmium ions. GPT was found to be much more sensitive to--SH reagents than GOT. There was unusual reaction to the two thiols used, cysteine and mercaptoethanol. Cysteine inhibited both the enzymes and mercaptoethanol activated GPT and inhibited GOT. Thiols in combination with iodoacetamide showed that the strong inhibitory effect of cysteine on both enzymes was reduced by iodoacetamide, but with mercaptoethanol the inhibitory effect on GOT was greater than when either of them was used alone, while GPT the effect of either counteracted each other. EDTA activated both enzymes and partially protected mercury inhibition of both enzymes and silver inhibition GOT only. It provided no protection against silver inhibition of GPT but complete protection of GPT against total inhibition by cadmium ions.     

Cloning, sequence, and expression of a cDNA encoding hamster UDP-GlcNAc:dolichol phosphate N-acetylglucosamine-1-phosphate transferase

UDP-GlcNAc:dolichol phosphate N-acetylglucosamine-1-phosphate transferase (GPT) catalyzes the initial reaction required for synthesis of dolichol-P-P-oligosaccharides. We report here on the sequence and expression of a full-length cDNA clone encoding hamster GPT. The cDNA predicts a protein of 408 amino acid residues including 10 hydrophobic segments. Several portions of the hamster GPT sequence constituting one-third of the protein have 60% or greater identity with yeast GPT, and one-half of the conserved sequence falls within the hydrophobic segments. In addition, hamster GPT has two copies of a putative dolichol recognition sequence recently identified in three yeast enzymes that interact with dolichol. The protein lacks KDEL or DEKKMP-type carboxyl-terminal ER sorting sequences. When expressed in COS-1 cells, the cDNA causes a 5-7-fold increase of GPT activity in membrane fractions. The activity was completely inhibitable by tunicamycin, and the primary product was shown to be GlcNAc-pyrophosphoryldolichol. This cDNA represents the first enzyme of the dolichol-oligosaccharide biosynthetic pathway to be cloned from a vertebrate source and demonstrates structural homology between the enzymes of the yeast and mammalian pathways.