Genetic studies of phosphoglucomutase-1 (PGM1) subtypes: population aspects]

Distribution of the subtypes and gene frequencies of phosphoglucomutase-1 among some populations of Buryats, Kirghizes of the Pamir and Russians of Moscow district was analysed. The frequencies of PGM1 genes vary in Buryats being PGM1+(1) 0.647-0.743, PGM1-(1)-0.100-0.132, PGM2+(1)-0.122-0.199 and PGM2-(1)-0.007-0.037. Following frequencies of PGM1 genes were established for Kirghizes: PGM1+(1) = 0.614, PGM1-(1) = 0.114, PGM2+(1) = 0.217 and PGM2-(1) = 0.054; in Russian populations the frequencies were: PGM1+(1) = 0.578, PGM1-(1) = 0.110, PGM2+(1) = 0.253 and PGM2-(1) = 0.059. Peculiarities of PGM1 polymorphism in the USSR and all over the world were analysed. Parallel biodemographic investigations in Buryat population demonstrated differences in intensities of selection, related to concrete PGM genotypes.     

Isoelectric focusing studies of human red cell PGM1 in Japanese, with special reference to the characterization of PGM17

The distribution of phosphoglucomutase (PGM1) subtypes in human red cells was determined by isoelectric focusing in 218 Japanese samples. Nine common phenotypes were observed corresponding to the following frequencies of the four alleles at the PGM1 locus: PGM11+ 0.6560, PGM11- 0.1170, PGM12+ 0.1674 and PGM12- 0.0505. In addition, a characterization of the PGM17 allele was performed. Our results obtained in the present study revealed the possibility that the PGM17 allele may be differentiated in the two alleles of PGM17+ and PGM17- through an investigation of isoelectric focusing.     

中国人红细胞PGM(PGM位点1)多态性的等电聚焦电泳研究

用等电聚焦电泳技术对北京地区180人进行红细胞葡萄糖磷酸变位酶(PGM_1)遗传表型的分析鉴定。共检测出九个PGM_1亚型,可能由于检测样本数还不够多,目前尚未检测到PGM_1 2-亚型。根据测定结果,观察了我国人群中PGM_1亚型的分布情况,并计算出决定PGM_1亚型的四个等位基因频率为:PGM~(1+)_10617,PGM~(1-)_1 0.100,PGM~(2+)_1 0.236,PGM~(2-)_10.047。采用等电聚焦电泳可将PGM_1的个体识别能力(DP值)由用普通淀粉胶电泳分型的0.558提高到0.742。结果与世界上其他国家和地区人群相似,PGM_1在我国人群中同样是一个个体识别能力很高的多态性酶类。     

Subtyping of human red cell phosphoglucomutase locus 1 (PGM1) polymorphism: a third PGM1(1) allele common among Twa Pygmies from North Rwanda.

Seventy-eight Twa Pygmies from North Rwanda have been subtyped by acid starch gel electrophoresis for the polymorphism at the phosphoglucomutase locus 1 (PGM1). A third common PGM1(1) allele that has been named PGM1(1Twa) was detected in heterozygous association with both PGM1(1S) and PGM1(1F) alleles. The PGM1(1Twa) product is faster than those of the other two PGM1(1) alleles and has the same electrophoretic mobility as the rare PGM1(6) enzyme. The frequency of PGM1(1Twa) was found to be 0.45.     

Electrophoretic subtyping of phosphoglucomutase locus 1 (PGM1) polymorphism in the Italian and Czechoslovakian populations

About 3,500 subjects from Italy and Czechoslovakia have been analyzed by acid starch gel electrophoresis for the subtyping of PGM1 polymorphism. The Italian sample included three different subgroups, from Northern, Central and Southern Italy. The allele frequencies found in the three groups do not differ significantly from each other; the observed values in the pooled sample are: PGM1S1 = 0.594, PGM1F1 = 0.118, PGM2S1 = 0.231, PGM2F1 = 0.057. In the Czechoslovakian group, which differs significantly from the Italian population, the following allele frequencies were found: PGM1S1 = 0.639, PGM1F1 = 0.118, PGM2S1 = 0.180, PGM2F1 = 0.063. The analysis of 217 families did not show any exception to Mendelian inheritance of the patterns.     

Purification and partial characterization of the phosphoglucomutase isozymes from human placenta

We have developed a simple procedure for the purification of phosphoglucomutase (PGM) isozymes from human placenta of healthy women. The technique involves the ammonium sulfate fractionation, ion-exchange and dye-ligand chromatographies. By this method we obtained homogeneous isozyme preparations of the products ("primary" and "secondary") of the two PGM1 and PGM2 loci. The final specific activities were 1134.6-1441.8 units/mg for PGM1 forms and 40.2-46.5 units/mg for PGM2 forms. On SDS-polyacrylamide gel electrophoresis analysis, the final preparations gave a single protein band of 58,500 and 69,000 Mr for PGM1 and PGM2 isozymes, respectively. These forms have the same kinetic properties, but from the substrate specificity experiments we have found that PGM2 forms are more effective for catalyzing the phosphoribomutase and glucose 1,6-bisphosphate synthase reaction than PGM1 forms. All these properties are shared by the same isozymes previously isolated from human erythrocytes but in this procedure the use of human placenta for the PGM isozymes purification takes advantage of high specific activity of PGM in the extracts of this tissue as well as obtaining highly homogeneous protein suitable for studies at molecular level.     

Subtyping of phosphoglucomutase locus 1 (PGM1) polymorphism in some populations of Rwanda: description of variant phenotypes, "haplotype" frequencies,and linkage disequilibrium data.

Some populations of Rwanda (South Twa Pygmies, Hutu, and Tutsi) have been analyzed by acid starch gel electrophoresis for the subtyping of PGM1 polymorphism. The new polymorphic third PGM11 allele, the PGM1(1Twa), which we recently detected in Twa Pygmies from North Rwanda, has not been found in this survey, whereas the rare PGM1(6) allele attains subpolymorphic frequencies in all groups. Comparison between the various populations of Rwanda shows that they differ significantly from each other with the exception of South Twa Pygmies and Tutsi. A relatively low frequency (9.6%) of the PGM1(2S) allele appears to be typical of North Twa Pygmies; a low frequency of PGM1(2F) (1.2%-3.6%) has been found in all these groups but not in the Hutu (6.4%); and a particularly high incidence of the PGM1(1F) allele (the highest so far reported) has been observed in the South Twa Pygmies (20%) and in the Tutsi (18%). The PGM1(1Twa) and PGM1(6) enzymes, which in acid starch gel are not distinguishable, can be clearly differentiated by isoelectric focusing. In addition, the same technique has shown that the rare PGM1(7) allele observed in one Hutu is different from that found at polymorphic frequency in the Japanese and from a rare PGM1(7) allele found in Germany. On the very likely hypothesis that the PGM1(1S), PGM1(1F), PGM1(2S), and PGM1(2F) result from variations at two different polymorphic sites, 1/2 and F/S, within the PGM1 structural gene, all the available population data have been analyzed to investigate whether preferential combinations (haplotypes) were identifiable. Whereas Caucasians show a prevalence of 2F and 1S combination with an 8.02% mean value of linkage disequilibrium expressed as % Dmax, from the very few and scattered African data, it is impossible to draw any inference at present.     

中国广东人红细胞PGM_1亚型遗传性多态现象

采用薄层聚丙烯酰胺凝胶等电聚焦技术,调查了中国(广东)406名无亲缘关系的正常人红细胞磷酸葡萄糖变位酶-1(PGM_1)亚型的遗传多态性。除了常见的10种亚型外,还发现了由一个新的变异型等位基因和常见的4个等位基因杂合产生的9例变异型。PGM_1位点的等位基因频率PGM_1~(1+)、PGM_1~(1-)、PGM_1~(2+)、PGM-1~(2-)和PGM_1~(V丰)(变异型等位基因)分别为0.5973、0.1256、0.1724、0.0936和0.0111;群体处于Hardy-Weinberg式平衡状态。变异型等位基因以多态频率出现,可能成为该群体的一个重要的遗传性特征。     

PGM1 system. Report on the international workshop, October 10-11, 1983, Munich, West Germany.

Because of the increase in the number of PGM1 polymorphisms and the existence of four distinct nomenclatures for expressing subtypes by isoelectric focusing, a nomenclature workshop was held in 1983 to compare variants and arrive at a single method for reporting PGM1 data. A total of 30 rare variants were identified and the recommended method for expressing the four common alleles is PGM1*1A, PGM1*1B, PGM1*2A, and PGM1*2B.     

Molecular and Biochemical Characterization of Cytosolic Phosphoglucomutase in Maize : Expression during Development and in Response to Oxygen Deprivation

Phosphoglucomutase (PGM) catalyzes the interconversion of glucose (Glc)-1- and Glc-6-phosphate in the synthesis and consumption of sucrose. We isolated two maize (Zea mays L.) cDNAs that encode PGM with 98.5% identity in their deduced amino acid sequence. Southern-blot analysis with genomic DNA from lines with different Pgm1 and Pgm2 genotypes suggested that the cDNAs encode the two known cytosolic PGM isozymes, PGM1 and PGM2. The cytosolic PGMs of maize are distinct from a plastidic PGM of spinach (Spinacia oleracea). The deduced amino acid sequences of the cytosolic PGMs contain the conserved phosphate-transfer catalytic center and the metal-ion-binding site of known prokaryotic and eukaryotic PGMs. PGM mRNA was detectable by RNA-blot analysis in all tissues and organs examined except silk. A reduction in PGM mRNA accumulation was detected in roots deprived of O₂ for 24 h, along with reduced synthesis of a PGM identified as a 67-kD phosphoprotein on two-dimensional gels. Therefore, PGM is not one of the so-called “anaerobic polypeptides.” Nevertheless, the specific activity of PGM was not significantly affected in roots deprived of O₂ for 24 h. We propose that PGM is a stable protein and that existing levels are sufficient to maintain the flux of Glc-1-phosphate into glycolysis under O₂ deprivation.     

Immunological studies on erythrocyte phosphoglucomutase isozymes

Human erythrocytes (phenotype PGM1 a1 or PGM1 a3) contain two sets of phosphoglucomutase isozymes, produced by the expression of the PGM1 and and PGM2 loci. The two sets are constituted each by two forms, of which that called "secondary" is thought to derive from the post-translational modification of that called "primary". Cross-reactivities of these isozymes were studied by means of monospecific rabbit antibodies against purified human red cell PGM1 and PGM2 "primary" isozymes. The results show that the PGM1 and PGM2 forms are not immunologically related and provide further proof of the post-synthetic origin of "secondary" isozymes and of the multifunctionality of PGM2 phosphoglucomutases.     

Phosphoglucomutase phenotypes and prenatal selection. Studies of spontaneous and induced abortions.

The PGM1 and PGM3 phenotypes were examined in extracts of chorionic tissue from 97 spontaneous and 266 induced abortions. Contamination by maternal tissue or blood cells was shown to be insignificant. A positive association was found between the PGM11 and PGM13 genes. No significant differences in phenotype distributions were found between the population of spontaneously aborted fetuses and the normal fetal or adult populations. Hence it was concluded that there is no evidence so far for prenatal selection operating in the PGM1 and PGM3 polymorphisms.     

Isoenzymes of phosphoglucomutase from human red blood cells: isolation and kinetic properties

A procedure has been developed for the purification of phosphoglucomutase from human red cell (phenotype PGM1 a1 or a3) lysates. It yields homogeneous isoenzyme preparations of the products ("primary" and "secondary") of the two PGM1 and PGM2 loci with distinctive pI (from 6.07 to 5.29). There are substantial differences between PGM1 and PGM2 isoenzymes, having single polypeptide chains of 58,500 and 69,000 Mr respectively and showing different thermostability. The kinetic properties of all the isoenzymes for the phosphoglucomutase reaction are essentially the same (apart from the specific activity of 1089-1263 units/mg for PGM1 forms vs 37-42 units/mg for PGM2 forms), but there are striking differences in substrate specificity. In fact the products of PGM1 locus are "true" phosphoglucomutases, being specific to mutate glucose monophosphates, whereas the PGM2 forms also display phosphoribomutase and glucose 1,6-bisphosphate synthetic activities. Some kinetic properties of these "side activities" are also reported.     

Molecular identification of mammalian phosphopentomutase and glucose-1,6-bisphosphate synthase, two members of the alpha-D-phosphohexomutase family

The molecular identity of mammalian phosphopentomutase has not yet been established unequivocally. That of glucose-1,6-bisphosphate synthase, the enzyme that synthesizes a cofactor for phosphomutases and putative regulator of glycolysis, is completely unknown. In the present work, we have purified phosphopentomutase from human erythrocytes and found it to copurify with a 68-kDa polypeptide that was identified by mass spectrometry as phosphoglucomutase 2 (PGM2), a protein of the alpha-d-phosphohexomutase family and sharing about 20% identity with mammalian phosphoglucomutase 1. Data base searches indicated that vertebrate genomes contained, in addition to PGM2, a homologue (PGM2L1, for PGM2-like 1) sharing about 60% sequence identity with this protein. Both PGM2 and PGM2L1 were overexpressed in Escherichia coli, purified, and their properties were studied. Using catalytic efficiency as a criterion, PGM2 acted more than 10-fold better as a phosphopentomutase (both on deoxyribose 1-phosphate and on ribose 1-phosphate) than as a phosphoglucomutase. PGM2L1 showed only low (<5%) phosphopentomutase and phosphoglucomutase activities compared with PGM2, but was about 5-20-fold better than the latter enzyme in catalyzing the 1,3-bisphosphoglycerate-dependent synthesis of glucose 1,6-bisphosphate and other aldose-bisphosphates. Furthermore, quantitative real-time PCR analysis indicated that PGM2L1 was mainly expressed in brain where glucose-1,6-bisphosphate synthase activity was previously shown to be particularly high. We conclude that mammalian phosphopentomutase and glucose-1,6-bisphosphate synthase correspond to two closely related proteins, PGM2 and PGM2L1, encoded by two genes that separated early in vertebrate evolution.     

Ectomycorrhizal fungi of Kashmir forests

All the macromycetes recorded in Kashmir and suspected to be mycorrhizal (77 taxa) are discussed in the context of the vegetational communities of Kashmir.     

Isoelectric subtyping of the PGM1 in the Icelandic population

Phenotypes for the red blood cell enzyme phosphoglucomutase (PGM1) were determined by isoelectric focusing for a population of 2,501 Icelandic individuals. All ten phenotypes were observed, and the frequencies of four alleles at the PGM1 locus were as follows: PGM1 1+=0.6875; PGM1 1−=0.1124; PGM1 2+=0.1419, and PGM1 2−=0.0582. These results have been compared with those found in other northern European populations.     

Phophoglucomutase first locus polymorphism as revealed by isoelectric focusing in Southern Africa

Eleven Southern African populations (representing European, Asian and Negroid populations) have been typed for the first locus phosphoglucomutase (PGM1) using isoelectric focusing (pH range 5.0-8.0) in acrylamide gels. The gene frequencies of the four common alleles at this locus in these populations were compared to those found previously in European and Negroid populations. Marked differences in gene frequencies were observed: Negroes have a lower PGM1(2-) compared with Caucasoids due to a lower PGM1(2-) frequency, Indians a relatively high PGM1(2) due to a higher frequency of the PGM1(2+) allele. The Afrikaans and Ashkenazim do not differ appreciably from their European counterparts. The appearances of the rarer PGM1(6) and PGM1(7) alleles on isoelectric focusing are described and some kinetic properties examined. The PGM2(2-1), or 'Atkinson' phenotype, can also be detected with this technique.     

A genetic study of two French Guiana Amerindian populations

Two Amerindian populations of French Guiana were investigated for plasma proteins and red-cell enzymes. In the Wayampi tribe, rare variants were identified in 4 systems. The corresponding alleles are designated AK1 3 Wayampi, PGM1 (4/10) Wayampi, PGM2 6 Wayampi, and TfD. In the Emerillon tribe, a variant allele of PGM2, designated PGM2 6 Emerillon, was identified. For three of the systems, PGM1, PGM2, Tf, similar isozymes have been described in other Amerindian populations. These findings suggest that the corresponding alleles may have the same origin.     

Genetic characterization of an alloalbumin, albumin Kashmir, using gene amplification and allele-specific oligonucleotides.

The molecular basis for albumin Kashmir was studied using the polymerase chain reaction to amplify a DNA fragment containing codon 501 in exon 12 of the human albumin gene. Southern blots of the amplified DNA were hybridized to oligonucleotide probes specific either for the normal allele of albumin or for albumin Kashmir. The results provide strong evidence that codon 501 in albumin Kashmir is AAG (lysine) instead of GAG (glutamic acid), thus confirming the protein sequences reported. This approach was used to characterize a bisalbuminaemic individual as a carrier for albumin Kashmir. Similar strategies may be devised to study the molecular basis and to identify carriers of other alloalbumins.     

缩胆囊素、胃泌素及丙谷胺对大鼠胆汁分泌的影响

本文旨在研究五肽胃泌素(P-Gas)、缩胆囊素(CCK)与其受体拮抗剂丙谷胺(PGM)单独静脉输注或联合应用对大鼠胆汁流量及胆汁成分排泌量的影响。结果表明:(1)P-Gas无利胆作用;(2)CCK-8仅少量增加胆汁及 HCO_3~-的分泌量;(3)PGM 明显地增加胆汁及胆汁中 HCO_3~-和 CI~-的排泌量,但胆酸分泌量不增加;(4)当 CCK-8 2.3μg/(kg·h)静脉灌注与 PGM 200mg 灌胃联合应用时,胆汁、HCO_3~-和 CI~-的排泌量进一步增加,但P-Gas 2μg/(kg·h)与 PGM 联合应用时的胆汁排泌量低于单独应用 PGM 组。以上结果证明:PGM 有明显的促胆汁分泌作用,其机制属于非胆酸依赖性利胆、而CCK-8只是胆汁分泌的微弱刺激剂,P-Gas 则无利胆作用。在 CCK-8与 PGM 二组间,似有促胆汁分泌的协同作用;但表现在 P-Gas 与 PGM 二组间的作用,似为一种拮抗作用。