Amyloid fibrils were isolated from spleen and thyroid obtained at autopsy from one patient (S.K.O.) of Jewish origin with familial amyloidotic polyneuropathy. Gel filtration on Sephadex G100 after solubilization in 5 M guanidine HCl yielded three major components with 14,000, 9,000, and 5,000 mol wt, respectively. The two larger components shared antigenic determinants with human prealbumin. Am...

The specific protonation state of amino acids is crucial for the physicochemical properties of proteins and their biological functions. These protonation states influence, for instance, properties related to hydrogen bonding, solubility, and folding. pKa calculations for proteins are, therefore, important and require, in principle, a specification of the most stable protonated and deprotonated ...

Hydrodynamic, chemical, and optical properties of arginine deiminase (EC 3.5.3.6) from Mycoplasma arthritidis are reported for the enzyme isolated from log phase cells. The s& +, and D’& values of the enzyme are 5.48 S and 5.87 x 10V7 cm’/s, respectively; the molecular weight is 87,300. Determination of the amino acid composition shows that about 45% of the residues are nonpolar. Another unique...

Short basic peptides from the HIV Tat protein bind specifically to a bulge region in TAR RNA, with a single arginine residue providing the only sequence-specific contact. The free amino acid arginine also binds specifically to TAR. Previous circular dichroism (CD) experiments suggested that peptide binding induces a conformational change in TAR. Here we confirm this observation using single arg...

The two morphologically different constituents of the mature elastic fiber, the central amorphous and the peripheral microfibrillar components, have been separated and partially characterized. A pure preparation of elastic fibers was obtained from fetal bovine ligamentum nuchae by extraction of the homogenized ligament with 5 M guanidine followed by digestion with collagenase. The resultant pre...

This report focus on phase behavior of polyethylene glycol (PEG)4000/ phosphate/ guanidine hydrochloride/ water system at different guanidine hydrochloride concentrations and pH. The binodal of the systems was displaced toward higher concentrations of the components with increasing guanidine hydrochloride concentrations. The partition coefficient of guanidine hydrochloride was near unity and in...

Arginine kinase (AK) was isolated from the longitudinal muscle of the sea cucumber Stichopus japonicus. Unlike the monomeric 40 kDa AKs from molluscs and arthropods, but like the cytoplasmic isoenzymes of vertebrate creatine kinase (CK), the Stichopus enzyme was dimeric. To explore the evolutionary origin of the dimeric AK, we determined its cDNA-derived amino acid sequence of 370 residues. A c...

It is unknown why the potencies and efficacies of long-chained guanidine-type histamine H2-receptor (H2R) agonists are lower at the H2R of human neutrophils than at the H2R of the guinea pig atrium. To elucidate these differences, we analyzed fusion proteins of the human H2R (hH2R) and guinea pig H2R (gpH2R), respectively, and the short splice variant of Gsalpha (GsalphaS) expressed in Sf9 cell...

Highly purified axial filaments have been prepared from the spirochete Treponema zuelzerae, which possess a fine structure similar to the "beaded" form of bacterial flagella. The preparations consist largely of protein but also contain small amounts of hexose (less than 1%). The buoyant density of these filaments is 1.29 g/cm(3). At pH 4.3, in the presence of 4 m urea and 10(-3)m ethylenediamin...

Penicillinase from Bacillus cereu.s 569 was purified and examined for homogeneity by sedimentation analysis, aminoterminal analysis, and vertical acrylamide gel electrophoresis. The enzyme preparation was shown to contain three distinct species of extracellular penicillinase which could be separated easily by gel electrophoresis. Kinetic studies failed to reveal any significant differences in t...