摘要:

Abstract—The photoreactivation of TMV–RNA‡ irradiated with either 253–7 mμ or 302 mμ light can be prevented by reconstitution of the virus from TMV–protein and the ultraviolet irradiated RNA. The prevention of photoreactivation by reconstitution is not irreversible as the RNA can be extracted from the reconstituted virus and is still capable of undergoing photor

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1967.tb08878.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

Abstract—The formation of pyrimidine dimers on ultraviolet irradiation of TMV‐RNA in water is demonstrated in the region from 254 nm to 302 nm. No dimer is present in either unirradiatedE. coliribosomal RNA or TMV‐RNA. Dimer formation was also examined in TMV‐RNA irradiated in the presence of 5times10‐6M proflavin, in high salt, on dry ice, and in 90% methanol. No correlation of pyrimidine dimers with any biologically defined lesion is presently possible and it is suggested that dimer may not be involved in the inactivation of this

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1967.tb08879.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

Abstract—A versatile irradiation apparatus for the quantitative study of photochemical reactions is described, which incorporates a commercial monochromator and utilizes a calibrated thermopile for the continuous measurement of light absorption during irradiation. The operating characteristics are discussed, and illustrative applications are cited. Using this apparatus, the quantum yield of the potassium ferrioxalate actinometer at 366 nm and 25d̀C was determined as 1.27 ± 0.01 for a 6.0 times 10‐3M solution, in excellent agreement with reported values of

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1967.tb08880.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

Abstract—pKvalues of ionisation equilibrium of thiazines dyes in their triplet state have been measured in aqueous solutions by spectroscopy. The triplet‐triplet absorption bands, in the red part of the spectrum, are given for thionine, azurs and methylene blue. It is shown that, in the pH range 4–9, the equilibria investigated correspond to a second protonation of thiazines dyes that occurs in the triplet state:3TH++ H+→3TH22+designating by3TH+the thiazine cation similar to the species stable in neutral aqueous so

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1967.tb08881.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

Abstract—The photodynamic binding of psoralen to DNA and RNA was shown using different methods. This binding was found to be mainly located either at thymine or uracil. The concentration and pH dependancy was studied. The photoproduct obtained with uridine was isolated paper chromatographically and was split into initial components photochemically.The results bring an evidence that psoralen with its 3,4‐double bond is able to form a cyclic derivative with the C6‐C6doble bond of thymine or u

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1967.tb08882.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

Abstract—The determination of the α‐ketoacids, glyoxylic and pyruvic in partial hydrolysates of fibrous proteins (keratin and fibroin) after exposition to u.v. light has allowed us to suggest a photooxydation mechanism for the α‐aminoacid residues of glycine and alanine in proteins. The primary reaction is believed to be the formation of the peptide radical ‐NH‐CR‐CO‐, and the breakdown of polypeptide chains is explained by the formation of α‐ketoacy

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1967.tb08883.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

Abstract—The determination of glyoxylic and pyruvic acids in oligo‐and poly‐, glycine and alanine shows that the peptide group is photooxydized, probably with the radical ‐NH‐CR‐CO‐ as an intermediate.The characterisation of pyruvic acid in glutathione and oxydized glutathione confirms the photolysis of the C‐S bond in combined cysteine and cystine.Finally, a comparison of the photoreactivity of peptides of the types aliphatic amino acid‐aromatic amino acid and aromatic amino acid‐aliphatic amino acid allows us to propose a selective mechanism for the transfer of excitation energy from the phenyl group to the preceding amino acid residue in th

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1967.tb08884.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY