Genetic polymorphism of mitochondrial glutamate-oxaloacetate transaminase in Japanese

Summary A survey of a number of unselected sera indicated the presence of a variant allele of mitochondrial glutamate-oxaloacetate transaminase (Got _m ²) in Japanese with appreciable frequency, which was confirmed in white blood cells. The mode of an autosomal codominant inheritance was confirmed by two independent family studies.     

Identification of human red cell glutamate-pyruvate transaminase (GPT) phenotypes by isoelectric focusing.

Isoenzymes of human red cell glutamate-pyruvate transaminase (GPT) were resolved by isoelectric focusing (IEF) of hemolysates in polyacrylamide gels at pH 5.0-7.0. The bands of enzyme activity required both alpha-ketoglutarate and L-alanine in the staining mixture for visualization, indicating that the bands were not lactate dehydrogenase or glutamate dehydrogenase. Phenotyping of 41 individuals by IEF, including types GPT 1, 2A, 1-2A, 1-2B, and 2A-2B, agreed with the typing results obtained by electrophoresis in starch gels and in polyacrylamide gels at acid and alkaline pH. Analysis of one kindred demonstrated autosomal codominant transmission of the rare GPT*2B gene through 3 generations. IEF facilitates phenotyping by permitting identification of the GPT types on a single gel with a considerable reduction in time and cost. Although no new variants were found in this investigation, IEF may be more powerful for the recognition of presently undetected variants of GPT.     

Genetic and biochemical studies on glutamate-pyruvate transaminase from Drosophila melanogaster

We have used electrophoretic variants of glutamate-pyruvate transaminase (GPT, E.C. 2.6.1.2) in Drosophila melanogaster to genetically map the structural gene to position 42.6 on the X chromosome. By pseudodominance tests over several deficiencies we have localized it cytogenetically to the interval 11Fl-2 to 12Al-2. The sedimentation constant (s _20,w) of the native enzyme was determined in sucrose density gradients to be 5.9 and the native molecular weight approximately 87,000. The similarity in physical properties to mammalian enzymes suggests that the enzyme may also be dimeric in D. melanogaster.     

Human red cell glutamic-pyruvic transaminase polymorphism in Serbia, Yugoslavia

The polymorphism of red cell glutamic-pyruvic transaminase (GPT) was studied in 277 unrelated voluntary blood donors from the population of Serbia (Yugoslavia). The following phenotype frequencies were observed: GPT 1 0.309, GPT 2-1 0.454 and GPT 2 0.206, while gene frequencies were: GPT1 0.556 and GPT2 0.454.     

Red cell glutamate-pyruvate transaminase gene frequencies in Gambia, West Africa.

The red cell GPT phenotypes have been determined in two village populations in Gambia, West Africa. A total of 887 people have been investigated. The results confirm the previous observations that the frequency of the GPT gene is far higher in African populations than Caucasian populations.     

Phenotypic distributions of red cell glutamate-pyruvate transaminase (E.C.2.6.1.2) isoenzymes in British and New York populations.

1444 persons of British nationality living in London, and 294 Caucasians, 258 Negroes, 310 Hispanic persons, and 151 Chinese persons living in New York were tested for glutamate-pyruvate transaminase phenotype. The Gpt1 frequency in the British population was found to be 0.5277, the Gpt2 frequency was 0.4716, and two GPT 3-2 persons were found. The Gpt1 frequencies in the New York population were: 0.4834 in Chinese; 0.5226 in Hispanic persons; 0.8101 in Negroes; and 0.5306 in Caucasians. Two Caucasians possessed the GPT 3-2 phenotype.     

Polymorphism of red cell glutamic-pyruvic transaminase in Japanese: gene frequencies in samples from Northern Japan.

The genetic polymorphism of red cell GPT was investigated by starch-gel electrophoresis in four samples from northern Japan including a sample of the Ainu of Hokkaido. The distribution of the Gpt1 gene frequencies among 10 samples excluding the Ainu so far examined showed heterogeneity. The geographical cline of Gpt1 gene frequency reported in southern Japan was not observed in northern Japan.     

Genetic polymorphism of haptoglobin subtypes in a Japanese population

Haptoglobin (Hp) subtypes have been determined in the Japanese population by polyacrylamide gel isoelectric focusing followed by immunoblotting and by two-dimensional polyacrylamide gel electrophoresis. In the present study, neuraminidase-treated plasma samples were used for subtyping of Hp, without prior purification. These samples were obtained from 372 unrelated healthy donors. Allelic frequencies were: Hp*1F = 0.0014; Hp*1S+ = 0.2688; Hp*2FF = 0.0000; Hp*2FS = 0.7284, and Hp*2SS = 0.0014. The phenotypic distribution was in good accordance with the Hardy-Weinberg equilibrium.     

Genetic polymorphism of PIF proteins in a Japanese population

Phenotype and gene frequencies of PIF (parotid isoelectric focusing variant) were determined in a series of individuals from eastern Japan. Among 422 unrelated individuals examined, 391 (92.66%) of PIF+ and 31 (7.34%) of PIF- phenotypes were observed; the gene frequencies were PIF+ = 0.729 and PIF- = 0.271.     

Genetic polymorphism of the complement C2 in Japanese

Summary Genetic polymorphism of the second component of human complement (C2) was investigated in 521 unrelated healthy adult Japanese using isoelectric focusing in polyacrylamide gel followed by a specific hemolytic overlay method. Besides the phenotypes reported previously (C, AC and BC), a relatively infrequent double-banded phenotype (tentatively named A'C) was observed. Moreover, a homozygous variant (A) and a heterozygous double variant (AB) were observed. The estimated frequencies for the common allele. C2 ² (=C2 ¹ ), and the variant alleles, C2 ^A , C2 ^B (=C2 ² ) and C2 ^A were 0.939, 0.034, 0.022, and 0.006, respectively.The results of further typing for HLA-A,-B,-C specificities indicated the presence of significant associations of C2 ^A with HLA-B15 and with A26, and of C2 ^B with HLA-Bw61. These findings support our previous observation that in Japanese there are allelic combinations showing linkage disequilibrium between C2 and HLA loci which are different from those in Caucasians, and that the C2 structural locus is more closely linked to HLA-B than to HLA-A.C2 hemolytic activities of each phenotypes were assayed. The mean activity of type AC sera was significantly higher than that of type C or type BC, while there were no differences in the activities among the types C, BC or A'C.Also presented are two pedigrees demonstrating the segregation of C2 with HLA alleles in which a homozygous C2A or C2B individual was observed.     

Glutamic-pyruvic transaminase activity related to red blood cell age.

Red blood cell glutamic-pyruvic transaminase (GPT) phenotypes and catalytic activities were studied in normal subjects and in patients with various hemolytic syndromes associated with reticulocytosis. To assess the effect of cell age of GPT activity, young cells were separated from older cells by centrifugation, and the catalytic activities were compared. In normal blood, there was a progressive fall in GPT activity from the top layer (younger cells) to the bottom layer (older cells), with a mean ratio of 1.90 plus or minus 0.42. Similarly, in the blood of patients with reticulocytosis, the enzyme activity of the reticulocyte-rich layer was higher than that of the layer containing older cells (mean ratio 1.94 plus or minus 0.95).     

Detritiation of L-[3-3H]alanine in the glutamate-pyruvate transaminase reaction.

The detritiation of L-[3-3H]alanine in the reaction catalyzed by pig heart glutamate-pyruvate transaminase was monitored in the absence or presence of lactate dehydrogenase. The results indicated that each monodirectional conversion of L-[3-3H]alanine to [3-3H]pyruvate resulted in the generation of 3HOH at a rate representing one-third of the total 3H flux. No isotopic discrimination in reaction velocity between tritiated and 14C-labelled L-alanine was observed. The mathematical modelling of the reaction revealed that, as a consequence of the detritiation process, the steady-state ratio in L-[3-3H]alanine/[3-3H]pyruvate does not inform on either the absolute or relative size of the amino acid and 2-keto acid pools.     

Human red cell glyoxalase I polymorphism

Human erythrocyte glyoxalase I has been subjected to starch gel electrophoresis, and its isoenzymatic forms have been visualized by a new positive staining procedure. The enzyme exhibits polymorphism and holds promise as a useful new genetic marker.     

Human red cell acid phosphatase polymorphism

Red cell acid phosphatase phenotypes were determined in 401 unrelated persons from Southwestern Germany. The frequencies of genes P^a, P^b and P^c were estimated to be p=0.328, q=0.630 and r=0.042.Experiences in 101 cases of disputed paternity with 151 men involved are reported. 22 men could be excluded from paternity on the basis of red cell acid phosphatase phenotypes.In all 140 mother-child-combinations tested the distribution of red cell acid phosphatase variants was compatible with the genetic model suggested by Hopkinson et al.Usefulness of the system in forensic cases of disputed paternity is discussed.Data contained in this paper will also constitute part of the thesis of cand. med. Karl-Henning Lichte.     

Genetic analysis of thiopurine methyltransferase polymorphism in a Japanese population

Thiopurine methyltransferase (TPMT) catalyses the S-methylation of thiopurine drugs such as 6-mercaptopurine, 6-thioguanine, and azathiopurine. Several mutations in the TPMT gene have been identified which correlate with a low activity phenotype. The molecular basis for the genetic polymorphism of TPMT has been established for European Caucasians, African-Americans, Southwest Asians and Chinese, but it remains to be elucidated in Japanese populations. The frequency of the four allelic variants of the TPMT gene, TPMT*2 (G238C), TPMT*3A (G460A and A719G), TPMT*3B (G460A) and TPMT*3C (A719G) were determined in Japanese samples (n=192) using polymerase chain reaction (PCR)-RFLP and allele-specific PCR-based assays. TPMT*3C was found in 0.8% of the samples (three heterozygotes). The TPMT*2, TPMT*3A and TPMT*3B alleles were not detected in any of the samples analyzed. This study provides the first analysis of TPMT mutant allele frequency in a sample of Japanese population and indicates that TPMT*3C is the most common allele in Japanese subjects.     

Genetic polymorphism of erythrocyte histone H1 in Japanese quail

Histone H1 from erythrocytes of Japanese quail was resolved in a sodium dodecyl sulfate (SDS)-polyacrylamide gel into five fractions differing in apparent molecular weights. A polymorphism of histone H1.1, H1.2, and H1.3 bands was detected among quail individuals. While some birds possessed either a high (phenotype .3+) or a low (phenotype .3+/.3-) level of H1.3, at least half of the quail population lacked this H1 band (phenotype .3-). Appropriate genetic crosses demonstrated that H1.3 behaved as though it was coded by a gene with two codominant alleles at an autosomal locus. Using two-dimensional polyacrylamide gel electrophoresis (acid-urea followed by SDS gels), it was found that birds .3+ contained polypeptides H1.b1 and H1.b'1; birds .3-, polypeptides H1.b2 and H1.b'2 with lower apparent molecular weights; and birds .3+/.3-, both types of polypeptides in equal proportions. The H1.b2 + H1.b'2 complement was not discernible in SDS gels, for it migrated together with H1.c' within band H1.4. It was found that a small number of birds lacking the H1.2 band in SDS gels failed to express histone H1.a. Since birds with phenotype .2- with a defective allele of the gene H1.a were simultaneously lacking the H1.3 band, it seems that the imperfect allele of the H1.a gene might be closely linked to the alleles producing H1.b2 + H1.b'2.