Activation of O(2) Uptake and NAD-Specific Isocitrate Dehydrogenase in Mitochondria Isolated from Cotyledons of Castor Bean by cis, trans-Abscisic Acid

The rate of O(2) uptake and the activity of NAD-specific isocitrate dehydrogenase (NAD-ICDH) of mitochondria isolated from castor bean cotyledons were increased by added cis, trans-abscisic acid (ABA) in an in vitro system, while the NADP-specific isocitrate dehydrogenase (NADP-ICDH) was not affected by cis, trans-ABA. Trans, trans-ABA showed only a slightly inhibitory effect on O(2) uptake. The V(max) value for the isotherm of isocitrate by the enzyme was also increased by cis, trans-ABA. The isocitrate K(m) value for the enzyme with cis, trans-ABA was calculated to be approximately 249.8 micromolar, while the S(0.5) for the enzyme without the ABA was 151.6 micromolar. The n value calculated from the slopes of Hill plots of the reaction velocity of NAD-ICDH against isocitrate concentration was 1.5 in the mitochondrial fraction in the absence of ABA, and cis, trans-ABA treatment decreased the value to 1.0. Cis, trans-ABA also partly overcame the inhibition of NAD-ICDH activity by ATP.

The water-holding capacity of the stratum corneum measured by 1H-NMR

The amount of bound water in the stratum corneum of the hairless rat was measured by using proton nuclear magnetic resonance (1H-NMR) spectrometry in the temperature range of -5 degrees C to -30 degrees C. A decrease in the bound water content was observed when the stratum corneum was extracted using water, a mixed solvent of chloroform:methanol (2:1), or a 1% sodium dodecyl sulfate (SDS) aqueous solution. However, extraction using a mixed solvent of acetone:ether (1:1) did not change the bound water content at temperatures above -20 degrees C. The lipids extracted by acetone:ether-extraction method consisted of sebaceous gland lipids, cholesterol, free fatty acids, and ceramides. In contrast, the lipids extracted by chloroform:methanol-extraction method contained more polar lipids such as sphingomyelin, which had the same amount of bound water in itself as that of the water-extracted stratum corneum. These results suggest that the polar lipids soluble in the chloroform and methanol mixture may contribute to enhance the bound water content. Therefore, it is hypothesized that the water-holding capacity of the stratum corneum is dependent on both the hygroscopic components such as the natural moisturizing factor (NMF) and the polar lipids, such as sphingolipids, existing in the intercellular spaces of the stratum corneum.

Hematoxylin stainable epidermal protein of the newborn rat. IV. The change of antigenicity in situ by transglutaminase as determined by an immunofluorescent study

Based on the activity of transglutaminase, the change of antigenicity in situ of hematoxylin stainable protein (HSP) purified from 3-day-old rat epidermis and located on the cell membrane region of the stratum corneum was investigated by indirect immunofluorescent technique using a polyclonal antibody against hematoxylin stainable protein. Three different techniques were employed: (i) the skin section was incubated with a commercial guinea pig liver transglutaminase (GLT), (ii) the skin section was incubated with an epidermal extract of Tris-HCl (EX), and (iii) the skin section was incubated with an epidermal extract of 1% Triton X-100 (EXT). The sections incubated in Tris-HCl or Triton X-100 were used as controls. Each incubation was done both in the presence and absence of Ca2+ ions. After these incubations, an indirect immunofluorescent technique using a polyclonal antibody was performed. In the presence of Ca2+ ions, the specific fluorescence of the cell membrane region of the entire stratum corneum cells disappeared after the preincubation with GLT. That of the lower one third of the stratum corneum disappeared after the incubation with EXT. In contrast, in the absence of Ca2+ ions, no preincubation with GLT, EX, or EXT showed any disappearance of the fluorescence anywhere in the stratum corneum. There was also no disappearance of the fluorescence in the control sections. These findings suggest that the antigenicity of HSP in situ could be lost by the activity of transglutaminase.

[The formation of monoclonal antibody to the cell membrane region of the stratum corneum and keratohyaline granules of newborn rat]

We have developed a monoclonal antibody to the cell membrane region of the stratum corneum and keratohyalin granules using rat hematoxylin stainable proteins as an antigen. These hematoxylin stainable proteins were partially purified utilizing preparative isoelectric focusing from 50 mM Tris-HCl buffer soluble fraction of newborn rat epidermis. The developed monoclonal antibody located in both sites of the cell membrane region of the stratum corneum and keratohyalin granules (Ted-R-3). In an immunoblotting study using two-dimensional electrophoresis, a single protein which had a molecular weight of 55 kd reacted. The amino acid analysis of the affinity purified antigen showed that glycine, serine and glutamic acid residues comprised 20.4%, 18% and 12.6%, respectively. However, histidine and cystine residues comprised only 2.8% and 0.12%, respectively.

The substrate of epidermal proteases--effects of in situ activation of epidermal thiol proteases on stratum granulosum cells

In newborn rat skin, disulfide bonds exist in the cell membrane of the stratum corneum and in the cytoplasm of the stratum granulosum. However, in the latter region, they can be detected after ethanol fixed epidermis remains for 2 weeks at 4 degrees C. Thus, the idea arose that the visualization of the disulfide bonds in the stratum granulosum may be caused by proteases. Therefore, the in situ effects by both activation and inhibition of epidermal proteases were examined in tissue sections. Cryostat sections which were fixed in cold ethanol (-20 degrees C, 98%) were incubated either in PBS, pH 7.4, containing 10mM 2-ME as a control or in an epidermal homogenate (15,000 x g supernatant fraction containing 2-ME) at 37 degrees C for 30 minutes and 4 hours, respectively, in order to activate the epidermal proteases and then reacted with NEM, 2-ME, and DACM in steps. Many minute fluorescent particles were seen in the stratum granulosum under both of the above conditions. However, with incubation in PBS without 2-ME, no fluorescent particles were seen. In addition, when the tissue was treated with NEM and zinc chloride before incubation, no fluorescent particles were seen. O-phenanthrolin remarkably inhibited the appearance of these fluorescent particles. In contrast, leupeptin and antipain only slightly inhibited the appearance of these fluorescent particles, and pepstatin and phenylmethylsulfonyl fluoride didn't inhibit at all. In general, as NEM and zinc chloride strongly inhibit thiol proteases, these findings suggest that presence of the minute fluorescent particles in the stratum granulosum could be due to the effects of proteases, especially thiol proteases.

The 55-kd keratohyalin granule protein has the same epitope as the 43-kd stratum corneum membrane protein: immunofluorescence and immunoblotting studies using a monoclonal antibody to the 55-kd keratohyalin granule protein

A monoclonal antibody (Ted-R-1) to the keratohyalin granules (KHGs) of the newborn rat epidermis was developed by immunizing mice with a pH 4.7 hematoxylin-stainable fraction of the extract in a 50 mM Tris-HCl buffer, pH 7.3, containing 10 micrograms/ml phenylmethylsulfonyl fluoride (PMSF) from the newborn rat whole epidermis. Using an indirect immunofluorescence technique, Ted-R-1 was located in two places: (a) the KHGs and (b) the cell membrane region of the stratum corneum. Under immunoelectron microscopy, the antigenic materials were located at the periphery of the KHGs. Immunoblotting analyses of the antigenic pH 4.7 fraction, the Tris-HCl extract from the stratum corneum, and the Tris-8M urea extract from freeze-dried whole skin demonstrated that there were 55 kd, 43 kd, and 78 kd polypeptides, respectively, with which Ted-R-1 reacts. No positive spot was seen in the dermal extract. The major amino acids of the 55 kd protein were glycine (24.4%), serine (17.3%), glutamic acid (14.1%), and alanine (7.7%), while the histidine residue was only 3.1%. On the basis of its amino acid composition, the 55 kd proteins is the third component of KHGs - in addition to histidine-rich and cystine-rich proteins.

Human hematoxylin-stainable protein of keratohyalin granules origin. I. Extraction and purification

A human hematoxylin-stainable protein (HSP) was extracted from the massive stratum corneum of epidermal cysts. This protein was purified in two steps; first, through preparative isoelectric focusing, and, second, by affinity column chromatography bound with the specific, monoclonal antibody to keratohyalin granules (Ted-H-1). In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the purified HSP consisted of two proteins (70 and 62 kilodaltons [kd]), but only the 62-kd protein was detected in the 15,000 g supernatant fraction of the extract using the immunoblotting technique. The amino acid composition of the purified HSP included 30% glycine, 15% serine, 12% glutamic acid, and 4% ornithine, but only 2.3% histidine. Using the indirect immunofluorescent technique, observation showed that the monoclonal antibody, Ted-H-1, to the HSP, formed as a result of the partially purified antigen, was located in three places: 1) the keratohyalin granules; 2) in the cell membrane region of the lower part of the stratum corneum of the skin samples (forearm, cheek, and back); and 3) the keratohyalin granules in the follicular epithelium and on the trichohyalin granules. Reaction product was not seen in either the acrosyringium or in the plantar epidermis. As two positively reacted proteins with the Ted-H-1 were detected in the Tris-HCl extract from the plantar stratum corneum by the immunoblotting assay, however, the above negative result in the indirect immunofluorescent studies may be due to the masking of the antigenic site of keratohyalin granules in vivo. This hematoxylin-stainable protein was synthesized as one component of the keratohyalin granules in the stratum granulosum and may have been transferred to the stratum corneum cell membrane region.

Similarity and dissimilarity in the stereogeometry of the active sites of thrombin, trypsin, plasmin and glandular kallikrein

The relationship between chemical modifications of arginine derivatives and inhibitory activity to trypsin, plasmin and glandular kallikrein was investigated comparing with that of thrombin and concluded as follows: The hydrophobic binding pocket, which has been reported previously to be stereogeometrically very similar in trypsin and thrombin, corresponded to the length of ethylpiperidine. Concerning the site (termed the P site) next to the hydrophobic binding pocket, there were large differences in stereogeometry between trypsin and thrombin; the binding site of trypsin extended further to allow propyl and phenyl group attached to piperidine, while that of thrombin would be much narrower and unable to allow them. The P sites of plasmin and glandular kallikrein resembled that of trypsin in being able to allow phenyl group. To substantialize the hydrophobic binding pocket and the P site, a (2R, 4R)-MQPA-trypsin complex model was generated using the results of X-ray crystallography of (2R, 4R)-MQPA and BPTI-trypsin complex by calculation to minimize van der Waals contacts, and it was of great use for understanding the geometry of the active sites of trypsin, thrombin, plasmin and glandular kallikrein.

The cystine-rich envelope protein from human epidermal stratum corneum cells

A cystine-rich protein has been extracted from the membrane region of stratum corneum cells with 50 mM Tris-HCl buffer, pH 7.3. The protein has been purified by molecular sieve chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and preparative isoelectric focusing. An antibody, raised to the purified protein, was located in the cell membrane region in the stratum spinosum, stratum granulosum, and the inner part of the stratum corneum. In addition, the antibody also reacted with the protein extracted from the outer part of the stratum corneum by the immunoblotting method. Amino acid analysis of the protein revealed a distribution of 4.3% cystine residues, 9% lysine, 18.5% glycine, and 12.6% glutamic acid residues. The isoelectric point was found to be 4.8 and the molecular weight of the protein was 16,000.

Viscometric and electron microscopic analysis of effects of griseofulvin and its derivatives on in vitro polymerization of microtubule proteins and depolymerization of microtubules

Griseofulvin and its sixteen derivatives were investigated by viscometry to examine their effects on in vitro polymerization and aggregation of microtubule proteins and depolymerization of microtubules. Of these compounds, eight pairs of enantiomers were compared in their activities. Electron microscopic studies were performed in several samples. The results indicate that in the C ring moiety of griseofulvin derivatives natural (+)-griseofulvin structure is essential to show their functions on microtubule proteins and microtubules.

Selective inhibition of thrombin by (2R,4R)-4-methyl-1-[N2-[(3-methyl-1,2,3,4-tetrahydro-8-quinolinyl++ +) sulfonyl]-l-arginyl)]-2-piperidinecarboxylic acid

The potency of thrombin inhibition by 4-methyl-1-[N2-[(3-methyl-1,2,3,4-tetrahydro-8-quinolinyl)-sulfony l]- L-arginyl]-2-piperidinecarboxylic acid (MQPA) depended on the stereoconformation of the 2-piperidinecarboxylic acid moiety. Ki values for bovine alpha-thrombin were 0.019 microM with (2R,4R)-MQPA, 0.24 microM with (2R,4S)-MQPA, 1.9 microM with (2S,4R)-MQPA, and 280 microM with (2S,4S)-MQPA. (2R,4R)-MQPA of the four stereoisomers of MQPA was also the most potent inhibitor for other trypsin-like serine proteases with Ki values of 5.0 microM for trypsin, 210 microM for factor Xa, 800 microM for plasmin, and 1500 microM for plasma kallikrein. Examination of the potency of thrombin inhibition by arginine derivatives related to MQPA in structure suggested the presence of a specific binding site for the carboxamide portion (C-terminal side). The relative inhibitory potency of the four stereoisomers of MQPA for trypsin was nearly identical with that for thrombin, suggesting that the specific binding site for the carboxamide portion is present in both enzymes. Modification of thrombin by phosphopyridoxylation or the presence of heparin did not significantly alter the binding of MQPA.

Isolation and Characterization of Inner Membrane-Associated and Matrix NAD-Specific Isocitrate Dehydrogenase in Potato Mitochondria

The isotherm for isocitrate oxidation by potato (Solanum tuberosum L. var. Russet Burbank) mitochondria in the presence of exogenous NAD is characterized by a hyperbolic phase at isocitrate concentrations below 3 millimolar, and a sigmoid, or positively cooperative phase from approximately 3 to 30 millimolar. The two forms of isocitrate dehydrogenase were separated and characterized following the sonication of mitochondria in 15% glycerol in the absence of buffer, followed by fractionation in a density step gradient to yield inner membrane and matrix components. The membrane-associated isocitrate dehydrogenase was found to have a Hill, or cooperativity, number of 1, while the Hill number of the matrix enzyme was 2.5. Upon digitonin extraction the cooperativity number of the membrane enzyme rose to 3.5. The isocitrate K(m) for the membrane enzyme was calculated to be approximately 5.9 x 10(-4) molar, while the S(0.5) for the matrix was 6.9 x 10(-4) molar. The NAD K(m) for both enzymes was 150 micromolar. Whereas the membrane enzyme proved indifferent to adenine nucleotides, the matrix enzyme was arguably inhibited by AMP and ADP, and inhibited some 25% by 5 millimolar ATP. Both enzymes were negatively responsive to the mole fraction of NADH, the membrane enzyme being 50% inhibited at a mole fraction of 0.26, and the matrix enzyme by a mole fraction of 0.32. The suggestion is offered that the enzymes in question constitute two forms of a single enzyme, one peripherally associated with the inner membrane, and one soluble in the matrix. It is proposed that a degree of regulation may be achieved by the apportionment of the enzyme between the bound and free forms.

Liposomal membranes. XIV. Fusion of liposomal membranes induced by polyisoprenoids as monitored by fluorescence quenching method

Fusion of the single-walled liposomes of egg phosphatidylcholine as induced by the polyisoprenoids such as solanesol, trans-ethyl decaprenoate (EDP), coenzyme Q10, and dolichol has been investigated adopting the fluorescence quenching method. Relative efficiency of the polyisoprenoids employed on the induced fusion of liposomes was a sequence of solanesol less than or equal to EDP much less than CoQ10, dolichol, which was consistent with the result previously obtained by the dye-release method.

[A simple method for radioimmunoassay of total estrogen in urine]

A simple and rapid radioimmunoassay (RIA) without extraction or purification was developed for Total Estrogen (conjugated and unconjugated estrogen) in urine from normal men and nonpregnant women. Antiserum used to RIA was produced by immunizing rabbits with estriol-16 alpha-glucuronide (E3-16-G)-BSA conjugates. Antiserum to E3-16-G.BSA significantly cross-reacted with E1 (100%), E2 (100%), E3 (100%), E3-16-G (100%), AND E3-17-G (100%) and did not react with other conjugated estrogen in urine. Urinary estrogen glucuronides and sulfates were gently hydrolyzed by beta-glucuronidase from Helix pomatia juice for 2hr (48 degrees C) without inhibition, and hydrolysis urine was directly applied to RIA. The results obtained from this direct method correlated well with the chromatographic purificating method, the extracting method and the Brawn-Kambegawa method (colorimetric method). This direct method is very useful for clinical application.

Electron-microscopic changes in xerosis senilis epidermis. Its abnormal membrane-coating granule formation

Skin specimens of patients with xerosis senilis were examined electron microscopically. The changes were as follows: (1) The electron density of the stratum corneum was uniformly low and no keratin pattern was observed in the lowermost cells of the stratum corneum. (2) The number of keratohyalin granules was decreased but their electron density was normal. (3) There were no lamellate membrane-coating granules formed in the cells of the stratum granulosum and there were many small vesicles which were similar in size and shape to membrane-coating granules, but lacked a lamellate internal structure. This abnormal vesicle formation occurred in the epidermis of the same xerosis senilis patients both in winter and summer. This observation indicates that the change in the formation of membrane-coating granules could be an age-dependent disorder of the differentiation of keratinocytes. (4) Being accompanied by an age-related reduction in lipid production, the deficient formation of membrane-coating granules leads to the disappearance of the lipid film which surrounds the stratum corneum cells. This and the reduction in the surface lipid originating in the sebaceous glands could result in an increase in transepidermal water loss leading to the asteatotic scaly stratum corneum seen in the skin of patients with xerosis senilis in winter.

Viscometric analysis of effects of cytochalasins on in vitro polymerization and depolymerization of microtubules

Nineteen cytochalasins including 6 natural cytochalasins, 2 natural aspochalasins, 7 natural chaetoglobosins and 4 their acetates were investigated by viscometry to examine their effects on in vitro polymerization and depolymerization of microtubules. Cytochalasin A was proved as an only active cytochalasin, confirming the studies of Himes et al., and others showed very weak or no noticeable effects. This results indicate that a wide range of effects of cytochalasins are not related to interactions with microtubules.

Dyskeratotic process of hyperkeratosis lenticularis perstans (Flegel). The abnormal formation of cystine-rich protein

The dyskeratotic changes in the lesions of hyperkeratosis lenticularis perstans were examined electron microscopically and histochemically. Under electron microscopy, the formation of keratohyalin granules was reduced and there was a lack of lamellar granule formation. In addition, the catabolic processes were disturbed, and ribosomal and mitochondrial structures remained, and lipid crystal-like structures were seen in the stratum corneum. The structure of the desmosomes of the stratum corneum was identical to that seen in the stratum spinosum. Staining with thiol-specific, fluorescent reagent, N-(7-dimethylamino-4-methyl-coumarinyl) maleimide (DACM) demonstrated strong fluorescence in the cytoplasm of the stratum corneum and granulosum without reduction by 2-mercaptoethanol. With reduction, moderate fluorescence was only seen at the periphery of the stratum corneum cells. These results indicate that there is a cystine-rich protein in the stratum corneum cells.