The avian sarcoma/leukemia virus protease (PR), purified from avian myeloblastosis virus has a native molecular mass of 26 kDa, suggesting a dimer structure. The enzymatic activity of PR has been characterized using synthetic peptide substrates. PR is most active at pH 5.5, 35 degrees C and 2-3 M NaCl. Under these conditions PR cleaves decapeptides which are resistant in low ionic strength. Thi...

ABSTRACT. Iodinated heterocyclic molecules are crucial structural components of many natural products, including hormones, vitamins, and medicines. The pharmaceutical survey is very interested in the investigation kinetics iodination N-(p-chlorophenyl)-3,5-dimethyl-1,1-dioxo-1,2-thiazine. rate directly dependent on concentration both 1,2-thiazine iodine under different molar ratios (1:10), (10:...

1. The effect of iodination on the distribution of peptide hormones into the aqueous two-phase dextran-polyethylene glycol system and on the solubility of these hormones in aqueous polyethylene glycol and in water was assessed. Hormones that were studied included insulin, glucagon and parathyroid hormone. 2. The partition coefficient of native insulin in the dextran-polyethylene glycol system s...

The site of iodination of thyroglobulin in the thyroid gland revealed through morphological studies was critically reviewed in relationship to biochemical points of view. The phylogenetic and evolutional aspects of this problem were also reviewed and discussed. To conclude, the present author wishes to emphasize the following: 1. In adult vertebrates whose thyroid follicular structure has been ...

Insulin receptors from human placenta have been labeled by using an oxidative iodination procedure (iodogen-mediated or chloramine-T-mediated), Bolton-Hunter reagent or [3H]acetic anhydride. The oxidative iodination procedure reduces the affinity for 131I-insulin and the receptor protein becomes fragmented into smaller pieces with an s20,w value of 5-6. However, treatment with Bolton-Hunter rea...

Five different quorum sensing peptides (QSP) were iodinated using different iodination techniques. These iodinated peptides were analyzed using a C18 reversed phase HPLC system, applying a linear gradient of water and acetonitrile containing 0.1% (m/v) formic acid as mobile phase. Electrospray ionization (ESI) ion trap mass spectrometry was used for the identification of the modified peptides, ...

Thyroglobulin has been iodinated at pH 9.35 and the distribution of iodoamino acids has been determined. Iodination results in a decrease in the tyrcsyl and an increase in the diiodotyrosyl difference spectra peaks. The spectral changes indicate that tyrosyl groups, which are more or less shielded from the solvent, can also react with iodine. Based on recent model studies on the rates of iodina...

Arachidonic acid undergoes iodination in the presence of hydrogen peroxide, iodide, and either eosinophil peroxidase, myeloperoxidase or lactoperoxidase. The profile of products generated by each of the three peroxidases is similar as determined by reversed-phase high-performance liquid chromatography. Structural analysis of the products indicate that: 1, each of the four double bonds in arachi...

B eginning in the early 1960s Rodrigo FierroBenitez and his colleagues (1) carried out an extensive series of studies of endemic goiter and cretinism in Ecuador. This chapter will review the most salient aspects of these findings. The investigations by Fierro-Benitez and his group were carried out mainly in eight rural villages in the north and central highlands of Ecuador where surveys indicat...