Biography:

In the past Richard G.H. Cotton has collaborated on articles with Judith M. Finger and David S. Secher. One of their most recent publications is Stability of protein and mRNA in human postmortem liver-analysis by two-dimensional gel electrophoresis. Which was published in journal Clinica Chimica Acta.

More information about Richard G.H. Cotton research including statistics on their citations can be found on their Copernicus Academic profile page.

Richard G.H. Cotton's Articles: (4)

Stability of protein and mRNA in human postmortem liver-analysis by two-dimensional gel electrophoresis

AbstractThe method of two-dimensional polyacrylamide gel electrophoresis has been used to investigate the post mortem stability of protein and mRNA in human liver. The electrophoretic mobility of proteins and of the in vitro translation products of the mRNA were found to be essentially unaffected by incubation of the liver at 37° C for up to 2 h or at 4°C for up to 16 h. This study indicates that the major protein and mRNA species in liver are stable enough following death to allow meaningful studies on tissue collected under standard autopsy conditions.

The biosynthesis of phenylalanine and tyrosine; enzymes converting chorismic acid into prephenic acid and their relationships to prephenate dehydratase and prephenate dehydrogenase

AbstractCell-free extracts of Aerobacter aerogenes and Escherichia coli were chromatographed on DEAE-cellulose and the eluates examined for some of the enzymes concerned in the conversion of chorismic acid into phenylalanine and tyrosine. Enzymes which are able to convert chorismate into prephenate (chorismate mutase) are eluted in two peaks of activity. The effects of phenylalanine and tyrosine on enzyme levels and activity showed that one of these enzymes (chorismate mutase P) is probably related to phenylalanine biosynthesis and the other (chorismate mutase T) to tyrosine biosynthesis. Chorismate mutase T travelled on DEAE-cellulose with prephenate dehydrogenase, (prephenate; NAD oxidoreductase (decarboxylating) the subsequent enzymic activity on the tyrosine biosynthetic pathway. The two activities were also affected simultaneously by mutation. Chorismate mutase P travelled on columns with the next enzymic activity on the pathway of phenylalanine biosynthesis, prephenate dehydratase, (prephenate hydro-lyase (decarboxylating)) and both activities were affected following mutation.In extracts of the A. aerogenes strain examined, but not in E. coli extracts, a second peak of prephenate dehydratase activity was eluted in the early column fractions. This activity, unlike the prephenate dehydratase travelling with chorismate mutase P is not inhibited by phenylalanine.It is suggested that, in the biosynthesis of phenylalanine and tyrosine, there are two enzymes or enzyme complexes metabolising chorismate, one leading through prephenate to phenylpyruvate and the other leading through prephenate to 4-hydroxyphenylpyruvate.

SPONTANEOUS MUTATION IN IMMUNOGLOBULIN GENES

ABSTRACTUsing a new method for screening animal cells in tissue culture, 7,000 clones of a mouse myeloma cell line (P3K) have been examined for the spontaneous occurrence of variants with defects in Ig synthesis. Variants which failed to secrete Ig were found at a high frequency. At a lower frequency variants which secreted an Ig of altered isoelectric point were detected. Analysis of these proteins and of mRNA suggested that such variants arise as a result of mutations in the structural genes coding for Ig H–chains. This constitutes the first case in which a somatic mutation in a structural gene has been correlated with an alteration in amino acid sequence.

Original ResearchCorrect heteroduplex formation for mutation detection analysis

Background:The majority of mutation detection methods for unknown mutations are polymerase chain reaction (PCR)-based methods dependent on the formation of heteroduplexes between wild-type and mutant strands of DNA.Methods and Results:This report discusses the difficulties associated with forming heteroduplexes with a large DNA fragment and the implications for subsequent mutation detection by the chemical cleavage of mismatch technique and other methods reliant on heteroduplex formation. It was found that the size and sequence context of the fragment being investigated inhibited correct heteroduplex formation. The problem was overcome by dividing the sequence into two overlapping fragments.Conclusions:Early identification of this problem in other fragments will help with the rapid optimization of PCR-based mutation detection methods.

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