Human hypoxanthine-guanine phosphoribosyltransferase

A mutant form of human hypoxanthine-guanine phosphoribosyltransferase (HPRTToronto) was isolated from erythrocytes of a male patient with gout due to a partial deficiency of enzyme activity. The tryptic peptides of HPRTToronto were mapped by reverse-phase high pressure liquid chromatography in an attempt to define the precise abnormality in its primary structure. Sequence analysis of the single aberrant peptide in HPRTToronto revealed an arginine to glycine amino acid substitution at position 50. A single nucleotide change in the codon for arginine 50 (CGA leads to GGA) could explain this substitution.     

The preparation and kinetics of lactate dehydrogenase attached to water-insoluble particles and sheets

1. The preparation of lactate dehydrogenase covalently attached to anion-exchange cellulose particles and sheets by use of a dichloro-sym-triazinyl dyestuff, Procion brilliant orange MGS, is described. 2. The stability and kinetic properties of these preparations were investigated. 3. An equation is derived to describe the change in concentration of a substrate when passed through a uniform bed of a substrate-inhibited enzyme. A number of theoretical curves are shown to illustrate the system. 4. A titrimetric assay for lactate dehydrogenase is described, and shown to be stoicheiometric over the range pH5.0-9.2. 5. The results are discussed in relation to previous work, and the effects of charged groups on the support, and of the diffusion film surrounding any particle in suspension, are treated qualitatively.     

The stem and bulb eelworm, Anguillulina dipsaci (Kühn, 1858): the importance of collating evidence on the behaviour of biologic strains

The results of experiments on the infection of many different plants with seven biologic strains of known history of the nematode, Anguillulina dipsaci (Kühn), are given, together with the results obtained by other investigators. The technique by which the nematode was induced to infect other host plants is described in detail. The biologic strain theory in relation to A. dipsaci is discussed, together with the merits of the trinomial system of nomenclature in connexion with unspecialized races. The factors concerned with nematode outbreaks receive consideration. The relationship that exists between flower colour in herbaceous phloxes and the degree of infection by A. dipsaci is presented.