Modulation by basic polypeptides of ATP-induced activation of tyrosine hydroxylase prepared from bovine adrenal medulla

The effects of basic polypeptides on the activation of adrenal tyrosine hydroxylase by ATP were investigated to show a possible involvement of macromolecular cell components in the regulation of the enzyme activity. Basic polypeptides caused an enhancement of the activation of tyrosine hydroxylase by low concentrations of ATP, and the potentiating effects of these polypeptides were observed to be dependent on their concentrations. Kinetic studies showed that basic polypeptides caused an increase in the Vmax of the ATP-activated enzyme for the cofactor without any change in the Km. These results suggest that basic polypeptides convert the enzyme from a nonsusceptible form to a form susceptible to ATP, thus resulting in the potentiation of the ATP-induced activation. Furthermore, the activation by ATP of tyrosine hydroxylase was not observed after treatment of the enzyme preparation with CM-cellulose, and the responsiveness of the enzyme treated with CM-cellulose to ATP was partially restored by addition of basic polypeptides. These observations suggest the possibility that macromolecular cell components, presumably basic proteins, may be involved in the regulation of the activity of tyrosine hydroxylase through their modulating effects on the sensitivity of the enzyme to ATP within the cell.     

Comparison of phosphofructokinases in submandibular glands of immature and adult rats

1. Phosphofructokinases (PFKs) in immature and adult rat submandibular glands were purified to near homogeneity, and their properties were compared. 2. PFK in immature gland was less sensitive to inhibition by ATP than adult PFK. 3. Saturation curve for fructose 6-phosphate of PFK in immature gland was less sigmoidal than that of adult PFK indicating the lower cooperativity of subunits in immature PFK. 4. Fructose 2,6-bisphosphate relieved PFK from inhibition by ATP in adult gland, but a similar effect was not clearly observed in immature gland PFK. 5. Adult PFK was a heterotetramer consisting of C-, M-, L-subunits, but in immature PFK another type of subunit, which was slightly smaller than L-subunit, existed in addition to C-, M- and L-subunits.     

A Nitrate Reductase-Inactivating Factor from Barley (Hordeum distichum L.) Leaves

A nitrate reductase-inactivating factor (NR-IAF) was detectedin a crude extract from 8-day-old barley (Hordeum distichumL. cv. Daisen-gold) leaves by chromatofocusing. The factor seemedto be a proteolytic enzyme with a cysteine residue at its activesite because 1) it was thermo-labile, and trypsin treatmentcaused loss of activity; 2) p-chloromercuribenzoic acid andiodoacetamide inhibited its activity; 3) leupeptin, an inhibitorof trypsin-like enzymes, also inhibited its activity; and 4)proteolytic activity toward azocasein was detected for the factorpreparation. The factor did not affect the activities of nitritereductase, glutamate dehydrogenase and xanthine oxidase. (Received March 22, 1983; Accepted July 30, 1983)     

Linkage analyses among five esterase loci in the laboratory rat (Rattus norvegicus)

A cluster of esterase loci has been identified on a segment of a rat linkage group V; however, the linear order of all the loci has not been established. We estimated the recombination frequencies of two locus combinations among five esterase loci (Es-1, Es-2, Es-3, Es-4, and Es-Si) and the linear order of the loci by using three sets of backcross matings: (1) (K:W × IS) × IS, (2) (K:W × IS) × IS, and (3) (SHR × W) × W). The linear order was determined to be Es-1-Es-4-Es-2-Es-3-Es-Si, although the order of Es-2 and Es-4 remains tentative. The sexinfluenced esterase (Es-Si) was demonstrated to be distinct from Es-1 and was proposed to be Es-Si locus with two alleles of Es-Si ^a (positive) and Es-Si ^b (null).This work was partly supported by Grants-in-Aid for Scientific Research, No. 339020 (1978), from the Ministry of Education, Science and Culture, Japan.     

Distribution of lipid microspheres incorporating prostaglandin E1 to vascular lesions

The intravascular distribution of 0.2 mu lipid microspheres (LM) containing prostaglandin E1 (lipo-PGE1) injected intravenously in spontaneously hypertensive rats (SHR) and arteriosclerotic rabbits was investigated by electron microscopic observation and quantification of radiolabelled compounds. LM were observed under an electron microscope to concentrate in subendothelial space of vascular walls, particularly in vascular lesions associated with hypertension or arteriosclerosis. Radiolabelled lipo-PGE1 accumulated more densely in the vascular walls than did free PGE1, and the difference was more conspicuous in vascular lesions. This indicates that lipo-PGE1 penetrates vascular endothelium and then accumulates in blood vessels to result in augmentation of the pharmacological action of prostaglandin. These findings suggest the usefulness of LM as a carrier of prostaglandin to vascular lesions.     

Physarum vitronectin-like protein: an Arg-Gly-Asp-dependent cell-spreading protein with a distinct NH2-terminal sequence.

A 70-kDa protein cross-reacted with anti-bovine vitronectin was isolated from slime mold Physarum polycephalum. The NH2-terminal amino acid sequence of the protein, referred to as Physarum vitronectin-like protein, did not share any homology with those of animal vitronectins. It had cell-spreading activity, which was specifically inhibited by an Arg-Gly-Asp (RGD)-containing peptide.     

Synthesis of 1-(5'-O-benzoyl-3'-deoxy-beta-D-glycero-pentofuran-2'-ulosyl)uracil and its alpha-anomer by [1,2]-hydride shift

In contrast with direct tosylation of 5'-O-benzoyl- (1d) or 5'-O-pivaloyl-1-beta-D-lyxofuranosyl-uracil (1e) with TsCl/pyridine, tosylation of the 2', 3'-O-dibutylstannylene derivatives (4d,e) of these compounds proved to give the 3'-O-tosyl derivatives 2d, e selectively. Coversion of 2d as a model to 1-(5'-O-benzoyl-3'-deoxy-beta-D-glycero-pentofuran-2'-ulosyl )uracil (5-beta) by base-induced [1,2]-hydride shift was examined under various reaction conditions, and the alpha/beta ratio of the product mixture (5-alpha, beta) determined by 1H NMR spectroscopy in each case. The BzOLi/DMF combination has proved to be most profitable for obtaining 5-beta.     

Local and systemic expression of inducible nitric oxide synthase in comparison with that of cyclooxygenase-2 in rat carrageenin-induced pleurisy.

Expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) is up-regulated in response to inflammatory stimuli. To evaluate the extent to which local pleural inflammation involves additional site in the pleural cavity and elsewhere, we investigated the time course of the levels of iNOS and its product in the inflammatory and other sites, and compared those with a level of COX-2 in rat carrageenin-induced pleurisy. The exudate and plasma NOx levels rose, reaching peaks at 9 and 14 h, respectively. Both COX-2 and iNOS became detectable in exudate leukocytes, their levels reaching peaks at 3 and 9 h after irritation, respectively. COX-2 was detectable mainly in neutrophils, but iNOS was detectable in both neutrophils and mononuclear leukocytes. Furthermore, iNOS became detectable in neutrophils and mononuclear leukocytes in enlarged parathymic lymph nodes from 3h in addition to those in peripheral blood and Kupffer cells from 3 to 14 h, respectively. The gene product is also detectable in thymic large dendritic cells of pleurisy-induced rats as well as normal control rats. COX-2 became detectable in stellar dendritic cells of the enlarged draining lymph nodes from 14 h. Thus, these gene products were induced in the immediate proximity of regional lymph nodes, and even at a considerable distance of liver by the local inflammatory stimulus. Although their expression pattern was quite different from each other, these gene products were detectable in phagocytic cells.