摘要:

Summary1Four major enolase isozymes have been identified in human tissues and are referred to as L, M, ‘intermediate’ and ‘fast’. The M isozyme is the major form found in skeletal muscle and heart extracts and the L isozyme the major form found in extracts of liver and most other tissues The ‘intermediate’ and ‘ fast’ isozymes are most active in brain but are observed as weak components in most other tissues including heart but are not seen in skeletal muscle. It was observed that during fetal development of heart and skeletal muscle the L form declines in activity while the M form increases in activity.2The kinetic properties, heat stabilities and molecular sizes of the main enolase isozymes have been compared. Although the isozymes share many features in common, the ‘fast’ isozyme is more stable when subjected to heat treatment than either the L or M isozymes. Further, the ‘fast’ isozyme retains its dimeric structure and activity in the absence of magnesium ions while the L and M isozymes dissociate and lose activity. The ‘intermediate’ isozyme has properties which are intermediate to those of the L and ‘fast’ isozymes.3The ‘intermediate’ isozyme can be partially dissociated to equal quantities of L and ‘fast’ isozymes by storage at room temperature or by freezing and thawing in the presence of 2 m‐NaCl. Conversely, mixtures of L with ‘fast’ and M with ‘fast’ give rise to an ‘intermediate’ isozyme after freezing and thawing.4Evidence derived from this study has led to the suggestion that three separate gene loci are involved in the determination of human enolase. It is proposed that one of these,ENO1, determines the L isozyme which is the homodimer αα;another locus,ENO2, determines the ‘fast’ isozyme which is the homodimer ββ; and the third locus,ENO3, determines the M isozyme which is the homodimer γγ. The ‘intermediate’ isozyme seen as a strong component in brain and as a weak component in most other tissues is thought

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1976.tb00130.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummaryFour different cellogel electrophoretic patterns of enolase were found in human tissue extracts. They consisted cf:(A) one strongly stained band (I) and two minor bands (II and III) found in haemolysates, white cell, skin fibroblast and kidney extracts;(B) a three‐banded pattern in brain resembling that of haemolysates except for heavier concentrations of bands II and III;(C) a single component corresponding to band I, found in liver, heart, intestine, spleen and placenta;(D) a single band with slightly faster mobility than band I, found in adult muscle extracts.The haemolysate of an individual with the heterozygousENO11/ENO21, genotype had a triple‐banded pattern replacing band I, a double‐banded pattern replacing band IP and a single weakly staining band III. This finding, as well as the results of dissociation and recombination experiments, supports the hypothesis that the enzyme is a dimer formed by random interaction of two polypeptide chains (α and β) synthesized by two independent gene loci (ENO1, andENO2,). Evidence for a third locus,ENO3, is supplied by the electrophoretic pattern of

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1976.tb00131.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummaryIf a disease can be split into two or more groups on any criterion (clinical, biochemical, physiological or statistical) then the grouping can be tested to establish if genetically independent forms of the disease have been identified. The data required are simply the frequencies of the two disease groups in relatives of probands for each of the disease groups. A systematic search for such distinct groups is proposed in searches for genetic heterogeneity in familial diseases.

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1976.tb00132.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummaryDNA‐repair and the frequency of chromosome aberration after u.v. and X‐ray irradiation was studied on leukocytes from patients with Down's syndrome.The u.v.‐induced DNA‐repair synthesis was followed by the incorporation of [3H]thymidine in the presence of hydroxyurea. Similar dose‐response curves were estabIished for Down's syndrome leukocytes and controls. The cells from patients with Down's syndrome incorporated 70–75 % of the activity of control cells at the various doses (32–196 erg/mm.2). This difference was significant for the two highest u.v.‐doses (P<0.01). The yield of dicentric chromosomes after X‐ray exposure (150 rad.) was 35% higher in Down's syndrome leukocytes than in the contro

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1976.tb00133.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummaryThe tissue distribution of the adenylate kinase isozymes in man has been examined using various substrates. The isozymes attributable to theAK1andAK2loci were identified, and an additional set of isozymes probably attributable to a third locus was also found. This locus has been provisionally designatedAK3.The AK3isozymes show activity with either GTP + AMP or ITP + AMP but do not show activity with ATP + AMP. They also differ from the AK1end AK2isozymes in electrophoretic mobility and from the AK1isozymes in being resistant to silver inhibition. They are similar in molecular size to the AK1isozymes whereas the AK2isozymes are apparently larger. The AK3isozymes evidently correspond to the enzyme nucleosidetriphosphate‐adenylate kinase (2.7.4.10

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1976.tb00134.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummaryRacial variation in the incidence of several common congenital malformations has been studied in Atlanta, Georgia. The white‐to‐black incidence ratios were substantially different from unity for single defects, while approximate equality of rates was noted for multiple defects. Amongst the specific malformations for which familial data were available, affected first‐ and second‐degree relatives were found only in the families of probands with single defects. It is postulated that these findings may indicate a more prominent function of the environment in the genesis of multiple malformations than is the case for single defects, the occurrence of which may be more strongly affected by non‐sporadic geneti

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1976.tb00135.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Summary1. The three structural gene loci of human alcohol dehydrogenase have been studied in liver, jejunum and lung from 300 newborns in a triracially mixed population of Bahia, Brazil.2. The frequency of theADH23allele was0,1392, suggesting that theADH23allele is less frequent in Negroes.3. A newADE2variant was identified. The electrophoretic pattern was interpreted as due to a new allele which is provisionally calledADH2Bahfa.4. By electrophoretic classification the ‘atypical’ variant was found in 2.8% of the sample. A question is raised regarding the ancestral origin of the ‘atypical’ variant in the population. Because this variant is common in Japanese it may have reached the present day population of Bahia through their American Indian ancestors.5. Subjective estimation of the proportions of β chains by giving scores to the liver isozymes αα, αβand βß showed a clear relationship between the fetal weight and the β chain activity.6. The proportion of β chains in the liver is significantly less when there is no enzyme activity in the lung, indicating some synchronous ‘turning on’ mechanism for alcohol dehydrogenase synth

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1976.tb00136.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummaryBirdet al. (1974) noted an interesting ‘anticipation’ phenomenon in Huntington's Chorea occurring in patients who inherited the gene from their father. More extensive samples from 165 pedigrees in the Low Countries permitted us to show that most of this apparent ‘anticipation’ is an artifact due to sampling biases related to the year of birth categories of the affected parents. When these biases were excluded no differences exist between the ages of death of affected mothers and their affected children, but a small difference of approximately two ymrs remains between affected fathers and their affected children. This is explainable by the observation that juvenile cases of Huntington's Chorea usually have inherited the abnormality from their

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1976.tb00137.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummaryData on centromeric linkage for trisomies 13 and 18 are presented. There is no substantial evidence that any of these loci studied are on either chromosome. There is weak evidence relating the locus defining the Kidd groups to chromosome 18.

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1976.tb00138.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummaryHistorical demography, surname concordance (isonymy), migration, and genealogy give a consistent description of population structure. The census size has averaged about 1400 over the last five centuries. Conjoined with an effective migration rate of 0.05 per generation as estimated by three different methods, this gives an evolutionary size of638, random kinship of 0–008 and inbreeding of 0.007 relative to the rest of Britain. The population structure of Barra is similar to other British isolates in the recent past, but an order of magnitude less inbred than slash‐and‐burn agriculturalists and Pacific Islanders. Some consequences for rare genes and polymorphisms are disc

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1976.tb00139.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY