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Biomedical subjects

J E Kay

Publications and source records attributed to J E Kay.

At least 73 records · Page 4Linked to original sources
PubMed1976

The mechanism of inhibition of initiation of protein synthesis in reticulocyte lysates by pyrocatechol violet.

1. Pyrocatechol violet inhibits the initiation of protein synthesis in reticulocyte lysates. It prevents the formation of 80-S initiation complexes by inhibiting the binding of mRNA to 40-S initiation complexes. 2. Pyrocatechol violet inhibits the hydrolysis of methionyl-tRNAmetf by reticulocyte lysates or reticulocyte cell sap. 3. Concentrations of pyrocatechol violet sufficient to inhibit initiation have little effect on amino acid activation. Higher concentrations of pyrocatechol violet were strongly inhibitory.

Animals↗
PubMed1975

Defective initiation on natural messenger RNA by cell free systems from Krebs ascites cells incubated at elevated temperatures.

1. Cell-free systems prepared from Krebs II ascites cells incubated at 45 degrees C have a much lower endogenous activity than those from cells incubated at 37 degrees C. The endogenous activity is mainly due to completion of polypeptide chains initiated in the intact cell. The low activity of the 45 degrees C system is due to a lesion in initiation in cells incubated at 45 degrees C. 2. Cell-free systems from cells incubated at 45 degrees C can translate efficiently poly (U) at 8 mM Mg2+. However, they initiate poorly on globin mRNA, indicating that these systems reflect the situation in the intact cell. 3. The lesion in globin mRNA translation in 45 degrees C systems can be overcome by addition of reticulocyte initiation factors. At saturation concentrations of factors, the response of a 45 degrees C system is restored to almost normal. 4. 45 degrees C systems from 40-S initiation complexes with methionyl tRNAfmet almost as efficiently as normal, but their ability for form 80-S complexes with globin mRNA is impaired, unless they are supplied with exogenous initiation factors.

Animals↗
PubMed1975

The control of protein synthesis during the stimulation of lymphocytes by phytohaemagglutinin. III. Poly(U) translation and the rate of polypeptide chain elongation.

1. Cell-free systems from phytohaemagglutinin-stimulated pig lymphocytes are much more active in both endogenous protein synthesis and the translation of poly(U) than those from unstimulated lymphocytes. 2. Addition of tRNA stimulates the translation of poly(U) and greatly reduces the difference between systems from stimulated and unstimulated lymphocytes. Endogenous protein synthesis is not increased by added tRNA. 3. Systems from stimulated lymphocytes have an increased capacity to form aminoacyl-tRNA with several different amino acids. This reaction is limited by the amount of tRNA present in the cell-free system. 4. The rate of polypeptide elongation is not affected by lymphocyte stimulation. The increased rate of protein synthesis must therefore be due to an increase in the frequency of initiation of the synthesis of protein molecules.

Amino Acyl-tRNA Synthetases↗
PubMed1973

Control of ornithine decarboxylase activity in stimulated human lymphocytes by putrescine and spermidine.

Ornithine decarboxylase activity in extracts of phytohaemagglutinin-stimulated human lymphocytes is rapidly and extensively inhibited by additions of micromolar concentrations of putrescine or spermidine to the culture medium. This inhibition is not due to feedback inhibition of the enzyme by putrescine, spermidine or their metabolites. Inhibition is dependent on the continuation of protein synthesis, but does not require RNA synthesis. The effect of putrescine is abolished when its conversion into spermidine by the cells is prevented.

Blood Proteins↗