Abnormal centrosome amplification in the absence of p53

The centrosome plays a vital role in mitotic fidelity, ensuring establishment of bipolar spindles and balanced chromosome segregation. Centrosome duplication occurs only once during the cell cycle and is therefore highly regulated. Here, it is shown that in mouse embryonic fibroblasts (MEFs) lacking the p53 tumor suppressor protein, multiple copies of functionally competent centrosomes are generated during a single cell cycle. In contrast, MEFs prepared from normal mice or mice deficient in the retinoblastoma tumor suppressor gene product do not display these abnormalities. The abnormally amplified centrosomes profoundly affect mitotic fidelity, resulting in unequal segregation of chromosomes. These observations implicate p53 in the regulation of centrosome duplication and suggest one possible mechanism by which the loss of p53 may cause genetic instability.

Mutagenic analysis of functional domains of the mos proto-oncogene and identification of the sites important for MAPK activation and DNA binding

We constructed in-frame deletion/replacement mutations in the Xenopus mos proto-oncogene that lie within conserved Mos-specific codons, but outside of the regions that are conserved among the src kinase family of genes. All gene products were assayed in vitro for kinase activity and in vivo for their ability to induce oocyte maturation, embryonic cleavage arrest and cellular transformation. Most mutations in Mos eliminated both kinase and biological activity. However, a mutation in Mos that removed two basic amino acid residues (R94 and K97) downstream from the lysine at the ATP binding site (K90) markedly enhanced autophosphorylation activity. Moreover, this mutant displayed markedly reduced biological activity, lacked transforming activity, and failed to activate mitogen activated protein kinase (MAPK). A second mutant Mos product, lacking amino acids R45-A54, displayed a five-fold increase in cellular transforming activity. This Mos mutant specifically localized to the cytoplasm; in contrast to wild-type (wt) Mos that localized to both the nucleus and the cytoplasm. These data indicate that Mos transforming activity is mediated via signalling exerted in the cytoplasm, presumably through MAPK, and that nuclear localization of the oncogene product interferes with transforming activity. We also show that amino acids R45-A54 are important for Mos DNA binding activity.

Mos overexpression in Swiss 3T3 cells induces meiotic-like alterations of the mitotic spindle

High levels of mos protooncogene product are expressed during oocyte meiotic maturation and Mos has been implicated in formation of the spindle and spindle pole. Here, we show that in Swiss 3T3 cells with 4N DNA content, high levels of Mos lead to the production of binucleated cells. The Swiss 3T3 cells in mitosis, before binucleation occurs, are anastral and the spindle poles are juxtaposed to the cell membrane. These phenotypes may be related to the meiotic process of attachment of the spindle pole to the oocyte membrane during polar body formation. The production of binucleated somatic cells could result from attachment of the altered mitotic spindle pole to the cell membrane that interferes with cytokinesis but not karyokinesis. This can explain at least one form of genetic instability that leads to altered DNA content in tumor cells.

Determination of v-Mos-catalyzed phosphorylation sites and autophosphorylation sites on MAP kinase kinase by ESI/MS

MAP kinase kinase (MAPKK), a key component of the MAP kinase cascade, is activated through phosphorylation by several protein kinases, including the oncogene v-Mos and its cellular counterpart, c-Mos. The v-Mos-catalyzed phosphorylation sites on recombinant MAPKK1 were identified by electrospray ionization mass spectrometry as S218 and S222, located within a sequence that aligns with the T loop structure of cAMP-dependent protein kinase; these are the same as the Raf-1 phosphorylation site identified previously [Alessi, D. R., et al. (1994) EMBO J. 13, 1610-1619]. Phosphorylation of these sites was kinetically ordered, with S222 preferred over S218. Intramolecular autophosphorylation of these sites was kinetically ordered, with S222 preferred over S218. Intramolecular autophosphorylation of MAPKK occurred at several residues and was increased upon the stimulation of MAPKK activity by v-Mos. Major autophosphorylation sites were residues S298 and Y300. Minor autophosphorylation sites included T23, S299, S218, and either S24 or S25. Sequence similarities were noted between MAPKK autophosphorylation sites and exogenous phosphorylation sites on MAP kinase. Phosphorylation of either S218 or S222 was sufficient for partial MAPKK activation by Mos, and phosphorylation of S222 alone was sufficient for autophosphorylation at S298 and Y300. Mass spectral analysis was also performed on MAPKK1 purified from rabbit skeletal muscle. The peptide containing S218 and S222 was observed in only a singly phosphorylated form, and the peptide containing S298, S299, and Y300 was observed in multiply phosphorylated forms, suggesting that MAPKK is only partially phosphorylated within the T loop but significantly modified in the autophosphorylation loop under physiological conditions.

Overexpression of mos oncogene product in Swiss 3T3 cells induces apoptosis preferentially during S-phase

When Swiss 3T3 cells are acutely infected with Moloney murine sarcoma virus containing the v-mos oncogene, 90% of the cells round up and detach from the monolayer (floating cells) and express high levels of v-Mos. The majority of the floating cells are generated between 30 and 70 h post infection when the cellular level of Mos reaches approximately 0.1% of the total protein. Seventy percent of the floating cells exclude trypan blue but are growth arrested with 2C or 4C DNA content, whereas the remaining floating cells with < 2C DNA content, are dead or dying, and show characteristic apoptotic phenotypes. The apoptotic cells are most likely generated from cells in S-phase since these cells are absent from the viable floating cell population and the percentage of cells with < 2C DNA approximated the expected S-phase fraction of logarithmically growing cells. In addition, 5'-bromo-2'-deoxyuridine-labeling studies showed that approximately 50% of the floating cells with typical apoptotic phenotypes were metabolically-labelled with the drug. These analyses show that cell populations in different stages of the cell cycle are differently affected by high levels of v-Mos expression and cells in S-phase appear to be uniquely sensitive and undergo apoptosis.

Similarities between somatic cells overexpressing the mos oncogene and oocytes during meiotic interphase

The mos protooncogene encodes a serine/threonine kinase and is a key regulator of oocyte meiotic maturation. After acute infection of Swiss 3T3 cells with virus containing the v-mos oncogene, cells expressing high levels of v-Mos round up and detach from the monolayer (floating cells), while cells that remain attached express 10-fold lower levels of v-Mos and are transformed. The floating cells are growth arrested with their chromosomes partially condensed in the absence of histone H1 kinase activity, while mitogen-activated protein kinase activity is very high. Collectively, these properties are similar to properties observed in maturing oocytes between meiosis I and II. In v-mos-transformed cell populations, mitogen-activated protein kinase activity is also elevated, correlating with the degree of morphological transformation and the level of Mos expression. Moreover, phosphoprotein modifications specific for M are found in both the floating cells and in v-mos-transformed cells, regardless of their cell cycle stage. One explanation for both morphological transformation and the phenotypes of the floating cells is that Mos imposes a meiotic program on different stages of the somatic cell cycle. The extent of this meiotic phenotype is proportional to the level of v-Mos expression. These results suggest that both morphological transformation and the phenotypes of the floating cells induced by Mos in Swiss 3T3 cells are related to its normal activities during oocyte maturation.

Transformation of mammalian cells by constitutively active MAP kinase kinase

Mitogen-activated protein (MAP) kinase kinase (MAPKK) activates MAP kinase in a signal transduction pathway that mediates cellular responses to growth and differentiation factors. Oncogenes such as ras, src, raf, and mos have been proposed to transform cells by prolonging the activated state of MAPKK and of components downstream in the signaling pathway. To test this hypothesis, constitutively active MAPKK mutants were designed that had basal activities up to 400 times greater than that of the unphosphorylated wild-type kinase. Expression of these mutants in mammalian cells activated AP-1-regulated transcription. The cells formed transformed foci, grew efficiently in soft agar, and were highly tumorigenic in nude mice. These findings indicate that constitutive activation of MAPKK is sufficient to promote cell transformation.

Chromophobe renal cell carcinoma: a report of two cases

Chromophobe renal cell carcinoma (RCC) is a recently established subtype of RCC, which has rarely been reported in Japan. In this communication, the authors report two Japanese cases of chromophobe RCC together with the immunohistochemical findings. The tumors were composed of sheets and cribriform glands formed by tumor cells with cloudy and reticular cytoplasm. Ultrastructurally, the cytoplasm was filled with numerous microvesicles. The tumor cells were positive for cytokeratin, epithelial membrane antigen, and Tamm-Horsfall protein. Occasionally, LeuM1-positive cells were also noted. Vimentin was negative, unlike the usual RCC. Reactivity for peanut agglutinin was more frequent than that to Lotus tetragonolobus agglutinin. The results of this study suggest that the tumor cells possessed phenotypes similar to the distal nephron rather than to the proximal tubular cells.

Ubiquitous nuclear proteins bind to 5' upstream region of major Kunitz chymotrypsin inhibitor gene in winged bean

Winged bean Kunitz chymotrypsin inhibitor (WCI) accumulates abundantly in seeds and tuberous roots of winged bean plant. In seeds, the WCI mRNA is observed transiently during seed maturation period. The WCI is encoded by a multigene family and the major WCI (WCI-3) is encoded by two nearly identical genes (WCI-3a and WCI-3b genes), in which nucleotide sequences in the 1.1 kb 5' flanking regions are about 99% homologous to each other and the transcribed regions are completely identical. Here we report the detection of two types of nuclear proteins which bind to the multiple sites in the 5' upstream region of the WCI-3a gene. One of the proteins, band 1-forming protein, also bound to cauliflower mosaic virus 35S (CaMV35S) promoter, but another protein, band 3-forming protein, did not. DNaseI footprinting analysis showed that these proteins bound to AT-rich upstream regions in the WCI-3a gene. Addition of poly(dA-dT)-poly(dA-dT) to the binding reaction inhibited the formation of the retarded bands, while poly(dI-dC)-poly(dI-dC) did not. In various organs and throughout seed maturation period, proteins with invariable binding specificities were detected, and these binding proteins met some operational criteria for high-mobility-group (HMG) proteins. These results suggest that leguminous seed AT-binding proteins reported on several seed storage protein genes may be HMG-like proteins which are present ubiquitously in plant organs.

[Characteristics of day service center clients and their families based on their medical conditions]

Clients utilizing day service centers in Hokkaido, and their families were surveyed for the purpose of analyzing present conditions of health, ADL level, family structure, motivation, activities, and changes in physical and psychosocial status. The average age of subjects was 76 years old with women generally being older than men. Most were living with their families. As to disease, cerebrovascular diseases were most common followed by hypertension and spinal-articulation diseases. Women had more hypertension problems compared to men who had more cerebrovascular conditions. Effectiveness of these day service programs were seen in the improvement of psychological functions. Persons with cerebrovascular disease had greater participation in functional rehabilitation training programs, and their ADL skills were improved.

[Effects of anesthesia on the metabolic response during pelvic surgery]

Dividing anesthesia for gynecological laparotomy into nitrous oxide-oxygen-halothane (GOF) anesthesia (group A), nitrous oxide-oxygen (GO) plus ketamine anesthesia (group B) and GOF plus epidural anesthesia (group C), we studied effects of each anesthesia on circulatory and metabolic systems. During the operation, influence on the heart rate was slight in three groups, while systolic pressure decreased significantly in group C. The lactic acid in the blood was elevated in three groups, but the elevation was least in group C. The elevation of lactic acid pyruvic acid ratio (L/P) was less in group C. The blood glucose level was elevated significantly in three groups, and it was highest in group A. On the other hand NEFA was elevated significantly in group A, while no change was noted in group B, and decreasing was noted in group C. The results indicate that no large influence of each anesthesia on the metabolic system was noted in group A and B, and its influence was the least in group C.

Hypertension in unilateral atrophic kidney secondary to ureteropelvic junction obstruction

A patient with atrophic unilateral hydronephrosis due to ureteropelvic junction obstruction associated with hypertension was successfully treated by nephrectomy. Preoperatively, plasma renin activity was elevated in both the peripheral vein and affected renal vein. Renin concentration in the resected kidney was high, and immunohistochemical localization of renin was observed along the afferent arterioles of the juxtaglomerular apparatus and in arterioles at some distance from the glomeruli.

Excess wild-type p53 blocks initiation and maintenance of simian virus 40 transformation

Wild-type (wt) murine p53 has been tested for its ability to block and reverse the transforming effects of simian virus 40 (SV40) large T antigen. Established and precrisis mouse cells overexpressing exogenously introduced wt p53 became resistant to SV40 transformation. The introduction of excess wt p53 into SV40-transformed precrisis cells reverted their transformed phenotype. However, the phenotype of SV40-transformed established cells was not reverted by excess wt p53. We conclude that an antioncogenic action of wt p53 is exerted during SV40 transformation and that in precrisis cells, the antitransforming action of wt p53 can be exerted both at initiation and during the maintenance of transformation.

Serum dipeptidyl peptidase activities as a possible marker of oral cancer

Serum glycyl-l-prolyl 4-methyl-coumaryl-7-amide (gly-pro-MCA) hydrolase (DPP IV) and L-lysyl-L-alanyl beta-naphthylamide (lys-ala-beta NA) hydrolase (assumed to be DPP II) activities were measured in patients with oral squamous cell carcinoma and healthy subjects. The mean serum DPP IV activity of all cancer patients was significantly (P less than 0.001) decreased, compared with that of healthy subjects. Although there was no significant difference between the stages by International Union Against Cancer (UICC) classification (1978), DPP IV levels tended to change dynamically, reflecting the clinical status during therapies. The serum DPP IV activity of patients with a fair prognosis was significantly elevated toward the normal range, whereas the activity of patients with a poor prognosis was significantly decreased (P less than 0.05). In contrast, the mean serum lys-ala-beta NA hydrolytic activity of cancer patients was significantly (P less than 0.001) increased, compared with that of healthy subjects, and was changed reciprocally to DPP IV activity. The correlation of these two serum enzyme activities with tumor weights also was observed in animal models using nude mice transplanted with human KB carcinoma cells and hamsters transplanted with BHK21 cells. These results indicate that these serum enzyme levels may become an aid for the diagnosis of malignant tumors and for estimating the prognosis of the patients.

The use of chitin as a new absorbable suture material--an experimental study

A comparative study of four absorbable suture materials, namely; poly-N-acetylglucosamine (Chitin), polyglycolic acid (PGA), plain catgut and chromic catgut, in terms of strength, elongation, tensile strength retention and tissue reaction, was undertaken. The straight pull strength of USP 3-0 size Chitin was over 2.6 kg, compared with PGA, which was over 3.4 kg and the catguts, which were over 2.0 kg. Chitin showed the lowest elongation among the four. The tensile strength retention (TSR) of Chitin in muscle was 45 per cent at 14 days and 7 per cent at 25 days, which was similar to that of PGA. The TSR of Chitin was maintained by 35 per cent in gastric juice, 97 per cent in bile and 100 per cent in pancreatic juice after immersion for 30 days. The corresponding values for PGA were 54 per cent, 0 per cent and 0 per cent, respectively, whereas both catguts had dissolved within 30 days. The tissue reaction of Chitin was similar to that of PGA, whereas the catguts caused more intense tissue reaction.

[Complications due to high-dose OK-432 administration into tumors and the peritoneal cavity in patients with advanced gastric cancer]

It has been assumed that a high dose of OK-432 can be safely injected into tumor tissues or intraperitoneally under general anesthesia. Among 40 patients with advanced carcinoma of the stomach, high doses of OK-432 were injected into the tumor in six and intraperitoneally in 34. Circulatory shock associated with subsequent disseminated intravascular coagulation (DIC) developed within 3 days in one of the former and in two of the latter group. Hypovolemic shock was initially considered to indicate that hypovolemia actually existed in these three patients. However, the shock state with DIC persisted even after the blood volume had been corrected. Gram-negative bacteremia was verified in two of the patients. The shock and DIC seen in these patients could have been attributed to septicemia through either the necrotic tumor or the intestinal wall showing increased permeability as a result of the drug. When and if a high dose of OK-432 is administered locally, the prophylaxis of infection seems to be of crucial importance in order to avoid such complications as those reported above.

Synchronous bilateral testicular tumors of different cell types on each side

Bilateral and synchronous testicular tumors consisting of different cell types on each side are rare. We describe one additional case of synchronous bilateral testicular tumors comprised of different cell types on each side and review the relative literature.

Alteration in dipeptidyl peptidase activities in cultured human carcinoma cells

For the investigation of the possibility of its being a marker enzyme for tumor cells, the activity of dipeptidyl peptidase (DPP) IV (EC 3.4.14.5), a membrane-bound enzyme, in cultured human carcinoma cells was examined. The homogenates of three carcinoma cell lines (HeLa, KB, and K-44) contained lower glycylprolyl methylcoumarinamide (Gly-Pro-MCA) hydrolase activities at pH 8.7 (assumed to be DPP IV) and higher activities of alkaline phosphatase and gamma-glutamyl transpeptidase, which are also membrane-bound enzymes, than those of normal human fibroblasts (HF). Examination of carcinoma cells for the subcellular localization and pH optimum of Gly-Pro-MCA hydrolase activity revealed that the activity of a lysosomal enzyme that hydrolyzes Gly-Pro-MCA at pH 6.4 was markedly increased in carcinoma cells, but not in normal cells. The separation and characterization of Gly-Pro-MCA hydrolases by gel filtration, affinity chromatography, and substrate specificity demonstrated that HF have three peaks indicating DPP IV, DPP II, and an unknown enzyme, whereas the three carcinoma cell lines gave a prominent peak indicating DPP II and a trace of DPP IV. The DPP II activity was 6- to 24-fold higher in carcinoma cell lines than in HF, and it also was 2.85- to 4.13-fold higher than the DPP IV activity in carcinoma cell lines but was 10-fold lower in HF. These clear enzymatic differences between carcinoma cells and normal HF may be useful as a marker of malignancy.

Metal ion inactivation and chelator stimulation of Streptococcus mitis arginine aminopeptidase

Activation of Streptococcus mitis (ATTC 9811) arginine aminopeptidase resulted in removal of the metal(s) from the enzyme molecule, and the action of the heavy metal ion in the inactivation process was shown to involve formation of a chelate complex between the enzyme molecule and metal or oxidation of functional group(s) on the enzyme surface. The enzyme also underwent activation by bovine serum albumin, amino acids, phosphate, and citric acid, which are probable physiological chelators.

Serum activities of dipeptidyl-aminopeptidase II and dipeptidyl-aminopeptidase IV in tumor-bearing animals and in cancer patients

Serum activities of dipeptidyl-aminopeptidases (DAP) II and IV were measured in tumor-bearing animals and in patients with blood and solid cancers using highly sensitive and specific fluorometric methods. In mice with intraperitoneal or subcutaneous implantation of Ehrlich ascites tumor cells, serum DAP II activity was increased and serum DAP IV activity was decreased, resulting in a significant increase in the ratio of serum DAP II and DAP IV activities. The increase in the ratio of these two activities paralleled the size of the subcutaneous tumors. However, both serum DAP II and DAP IV activities were increased in rats with experimental hepatic cancer induced by 3'-methyl-4-dimethylaminoazobenzene, and the increase in the ratio of the two activities was not significant. In cancer patients, as compared with healthy subjects, serum DAP II activity was increased and serum DAP IV activity was decreased, the ratio of serum DAP II and DAP IV activities being markedly increased in cancer patients. Both serum DAP II and DAP IV activities were increased in patients with hepatic cancer as were those in rats with hepatic cancer, but the increase in DAP II was greater than that of DAP IV; thus the ratio of the two activities increased significantly. These data suggest that the increase of the serum DAP II/DAP IV ratio could be a biochemical index of cancer.

Coordinate repression of arginine aminopeptidase and three enzymes of the arginine deiminase pathway in Streptococcus mitis

Streptococcus mitis contains two arginine aminopeptidases (I and II) as an arginine-supplying system and the arginine deiminase pathway as an arginine-utilizing system. The levels of arginine aminopeptidase I and three enzymes of the arginine deiminase pathway were suppressed by glucose in an apparently coordinate manner. Enzyme II appeared to be constitutive.

Inorganic pyrophosphatase activity of purified bovine pulp alkaline phosphatase at physiological pH

At physiological pH, the hydrolytic activity of purified bovine pulp alkaline phosphatase toward phosphorus compounds was observed to be in the order of inorganic pyrophosphate greater than beta-glycerophosphate greater than phosphorylcholine greater than p-nitrophenylphosphate greater than glucose-6-phosphate. Optimum pH of the enzyme toward inorganic pyrophosphate was shown to be 8.5, with around 60% of the activity at pH 7.5. The activity was increased by the addition of Mg2+, but a different pattern of activation was observed between pH 7.5 and 8.5.

Sandwich enzyme-immunoassay for dipeptidyl aminopeptidase IV in the serum of people with oral cancer

A highly-sensitive sandwich enzyme immunoassay for serum dipeptidyl aminopeptidase IV (DAP IV) was developed; its level in sera of patients with oral cancer [1.50 +/- 0.35(SD)mg/l serum] was significantly lower than in normal subjects [2.27 +/- 0.77(SD)mg/l serum].

Two-dimensional electrophoresis in the analysis of a mixture of human sublingual and submandibular salivary proteins

Complex protein mixtures of unstimulated human sublingual and submandibular saliva were fractionated by two-dimensional (2-D) gel electrophoresis, visualized by silver staining and then analysed by immunostaining. Specific proteins were identified by incubation with specific antibody and peroxidase-conjugated second antibody (Western blot). Electrophoresis and silver staining revealed over 50 protein components in 2 microliter of unconcentrated mixture. The Western-blot technique allowed detection of protein spots of plasma origin when an antibody against whole serum was used, but only the albumin spot could be found. Albumin, secretory IgA, acid phosphatase and alpha-amylase were identified with specific antibodies.

Depth of side-chain pocket in the S2 subsite of dipeptidyl peptidase IV

Kinetic studies of pig kidney dipeptidyl peptidase IV (dipeptidyl-peptide hydrolase, EC 3.4.14.5) were carried out using substrates possessing a side-chain of different length at the P2 position (or amino-terminal position in this case) such as Lys-, Arg-, Phe-, Met-, Ser-, His-, Glu- and Gly-Pro-pNA. The hydrolytic coefficient (Kcat/Km) has determined in the order Met- greater than Glu- greater than Ser- greater than His- greater than Phe- greater than Lys- greater than Gly- greater than Arg-, indicating a gradual increase with elongation of the side-chain from 0.03 to 0.60 nm followed by a decline when side-chain length approached 0.70 nm. Thus, the most probable depth of the side-chain pocket at the S2 subsite of the enzyme is proposed to be 0.50-0.60nm.

A sensitive and specific assay for dipeptidyl-aminopeptidase II in serum and tissues by liquid chromatography-fluorometry

A highly sensitive and specific method for the assay of dipeptidyl-aminopeptidase II (DAP II) in crude enzyme preparations such as serum and tissue homogenates has been established by using a newly synthesized fluorogenic substrate, 7-Lys-Ala-4-methylcoumarinamide. The enzymatically formed 7-amino-4-methylcoumarin was determined by high-performance liquid chromatography with fluorescence detection. The activities of other aminopeptidases in human serum and rat brain homogenates were completely inhibited by o-phenanthroline without any effect on DAP II activity to permit specific determination of DAP II. The limit of sensitivity for DAP II activity was about 300 fmol/30 min. DAP II activity was found to be increased in sera from cancer patients, in contrast to the decrease in serum DAP IV activity. DAP II activity was found to be unequally distributed in rat brain regions, and the highest activity was found in the hypothalamus.

Chemical modification of dipeptidyl peptidase iv: involvement of an essential tryptophan residue at the substrate binding site

Inactivation of pig kidney dipeptidyl peptidase IV (EC 3.4.14.5) by photosensitization in the presence of methylene blue at pH 7.5 was observed to have pseudo-first-order kinetics. During the process, until over 95% inactivation was achieved, the histidine and tryptophan residues were decreased from 14.0 to 2.7 and 12.6 to 7.1, respectively, per 94,000-Da subunit, without any detectable changes in other photosensitive amino acids. Modification of four histidine residues per subunit using diethylpyrocarbonate resulted in only 30% inactivation of the enzyme, while N-bromosuccinimide almost completely inactivated the enzyme with the modification of only one tryptophan residue per subunit, as determined by absorption spectrophotometry at 280 nm. The protective action of the substrate and inhibitors such as Ala-Pro-Ala and Pro-Pro against the modification of tryptophan residues with N-bromosuccinimide was observed both fluorometrically and by measurement of activity. On the basis of these results it is suggested that one of the tryptophan residues in the enzyme subunit is essential for the functioning of the substrate binding site of pig kidney dipeptidyl peptidase IV.

The effect of chronic isoproterenol administration on the plasma membrane of acinar cells in rat submandibular gland

The effect of chronic administration of isoproterenol on the plasma membrane of acinar cells in the rat submandibular gland was studied by biochemical and immunohistochemical methods, using dipeptidyl peptidase (DPP) IV as a marker enzyme. Chronic isoproterenol treatment led to a marked reduction of DPP IV activity as well as of its immunoreactivity in the gland. Its effect progressively increased with the age of the animals. The present study showed that chronic treatment with isoproterenol caused a qualitative alteration of the plasma membrane of the luminal surface in acinar cells of the rat submandibular gland, and that the effect of the drug on the plasma membrane was dependent on the developmental stage of the acinar cells of the gland.

[Serum tissue polypeptide antigen (TPA) in patients with urogenital cancer]

We measured the serum TPA level in 260 patients with benign urogenital diseases, 189 patients with urogenital cancer and 72 healthy blood donors by using a radio-immunoassay kit in order to evaluate its usefulness as an indicator for the presence of cancer. TPA value (mean +/- 2SD) in healthy blood donors was in the range of 36.8-110.8 units per liter, so that values higher than 110 U/L were considered to be abnormal. Significantly higher serum TPA levels were observed in patients with non-treated cancers, compared to healthy blood donors. But elevated serum TPA levels were also observed in the patients with benign diseases, especially in cases of benign prostatic hyperplasia with urinary tract infection. Consequently, it is considered that the serum TPA test is very useful for detecting urogenital diseases, but not for screening urogenital cancer. In cases of urogenital cancer, serum TPA levels elevated significantly by recurrence or recrudescence of the disease. Therefore, a good correlation was established between serum TPA and the efficiency of a given therapy in patients with prostatic cancer and bladder cancer.

Similarity between alkaline phosphatases from bovine dental pulp and liver

Specific antibody against purified alkaline phosphatase from bovine dental pulp was raised in a rabbit. Immunological analyses by Ouchterlony double-gel diffusion and quantitative immunoprecipitation showed that there was neither a detectable antigenic difference between liver and pulp alkaline phosphatases nor a detectable cross-reaction with the intestinal enzyme.

Purification and characterization of two novel arginine aminopeptidases from Streptococcus mitis ATCC 9811

Two novel aminopeptidases (I and II) which have specificity for amino-terminal arginine residues and strong sensitivity to divalent cations were purified from Streptococcus mitis ATCC 9811 by a procedure that involved treatment with a lytic enzyme for bacterial cell walls, followed by a series of chromatographies. Enzyme I was obtained as a homogeneous protein as judged by polyacrylamide gel electrophoresis and had a specific activity of 484.8 units per mg protein using L-arginine-2-naphthylamide as substrate; its Km value was 2.6 X 10(-5) M. The molecular weight was estimated to be 62,000, and its isoelectric point was pH 4.4. Enzyme II was purified to a specific activity of 128.0 units per mg protein and had a Km value of 3.8 X 10(-5) M. The molecular weight was estimated to be 360,000, and its isoelectric point was pH 5.7. The pH optima of enzymes I and II were 8.6 and 7.6, respectively. Both enzymes were inactivated by sulfhydryl reagents and metal ions but were markedly activated by EDTA. The chloride ion had an inhibitory rather than a stimulatory effect on the activity of both enzymes. Substrate specificity studies indicated that both the enzymes specifically hydrolyze N-terminal arginine residues from a-aminoacyl 2-naphthylamides and peptides, but they could not attack the L-arginyl-L-prolyl-peptide.

Characterization of a soluble form of dipeptidyl peptidase IV from pig liver

Soluble dipeptidyl peptidase IV (EC 3.4.14.5) was purified from the 100,000 X g supernatant fraction of pig liver homogenate. The purified enzyme had the same properties as, and immunological identity with, the membrane-bound enzyme which was described previously. However, the purified enzyme had a pattern of molecular heterogeneity different from the membrane-bound enzyme; this was shown by isoelectric focusing. Carbohydrate analysis revealed that the soluble enzyme contained glucose, which is not found in the membrane-bound one, and less fucose, mannose, and sialic acid than the latter. From these results, we conclude that the soluble form of dipeptidyl peptidase IV in pig liver is closely related to the membrane-bound enzyme, but is not simply a proteolytically solubilized product of it.

Purification and properties of dipeptidyl peptidase II from rat kidney

Dipeptidyl peptidase II (EC 3.4.14.2) from rat kidney was purified to a specific activity of 66.2 mumol/min per mg protein by a series of column chromatographic techniques. The purified enzyme was apparently homogeneous as judged by disc gel electrophoresis. Gel filtration on a calibrated column indicated an apparent molecular weight of 130 000 for the native enzyme. Gel electrophoresis of the denatured enzyme in the presence of sodium dodecyl sulfate in a constant acrylamide concentration resulted in the appearance of a single component for which a molecular weight of 64 000 was calculated. The pH optima for dipeptidyl arylamides and for tripeptides were pH 5.5 and 4.5, respectively, and the isoelectric point was 4.8. Substrate specificity studies indicated that the purified enzyme hydrolyzes specifically N-terminal X-alanine or X-proline from their respective arylamides and from tri- or tetrapeptides, but not from pentapeptides.

Serum dipeptidyl peptidase (DPP) IV activities in oral cancer patients

Dipeptidyl peptidase (DPP) IV activities in normal human sera and in the sera of patients with malignant tumors of the oral region were assayed. Patients with oral squamous cell carcinoma had significantly lower enzyme activity than that of normal controls (p less than 0.001). Patients with advanced carcinoma showed a more significant reduction of serum enzyme activity. On the other hand, in oral squamous cell carcinoma patients with hepatic dysfunction, the serum enzyme activity was significantly increased (p less than 0.02).

Arylamidase activities specific for proline, tyrosine, and basic amino acid residues in some oral bacteria

Arylamidase activities in eight strains of oral bacteria were assayed. Although the activities in S. mutans tested were low, S. mitis, S. milleri, and lactobacilli had high activities. Arylamidases which were specific for proline and basic amino acid residues in S. mitis and tyrosine residue in L. casei were identified.

Purification and properties of bovine dental-pulp alkaline-phosphatase

Alkaline phosphatase (E.C.3.1.3.1.) from unerupted bovine pulp was extracted from the microsomal fraction with eta-butanol and purified 77-fold, using DEAE-cellulose chromatography, Sephadex G-200 gel-filtration and concanavalin-A affinity chromatography, to a final specific activity of 92.3 units/mg protein. Affinity chromatography confirmed the glycoprotein nature of the enzyme. The pH optimum for the purified enzyme was 10.0 with rho-nitrophenylphosphate, and 8.7 with phosphoserine. The apparent Km was estimated to be 0.7 mM, using rho-nitrophenylphosphate in glycine-NaOH buffer, pH 10.0. The enzyme was markedly inhibited by EDTA, bromotetramisole and homoarginine but was insensitive to phenylalanine, and therefore resembled the alkaline phosphatase of liver and bone, but not that of intestine and placenta. No protein phosphatase activity towards dentine phosphoprotein and phosvitin was observed.

Phosphoprotein phosphatase activity of bovine intestinal alkaline phosphatase

The phosphoprotein phosphatase activity of a commercial preparation of bovine intestinal alkaline phosphatase (EC 3.1.3.1) was examined using phosvitin and dentine phosphoprotein as substrates. Over 90% and 70% of the phosphorus from dentine phosphoprotein and phosvitin were hydrolyzed in 2 h. The optimum pH of the enzyme for the dephosphorylation of phosvitin and dentine phosphoprotein was nearly 6. No protein phosphatase activity was observed when the alkaline phosphatases from bovine liver and pulp were investigated.

Immunohistochemical localization of dipeptidyl aminopeptidase IV in rat kidney, liver, and salivary glands

Specific antibodies directed against dipeptidyl aminopeptidase (DAP) IV prepared from rat and pig kidneys were produced in rabbits. Using a peroxidase-labeled or fluorescein isothiocyanate-labeled antibody method, localization of DAP IV was investigated in various tissues of the rat (kidney, liver and salivary glands). DAP IV was mainly localized in the brush border of the proximal tubules (kidney), in the cell membrane around bile canaliculi of hepatic cells (liver), and in the cell membrane of serous acinar cells (parotid and submaxillary glands). These results substantiate that DAP IV is a membrane-bound peptidase.

Comparison of dipeptidyl peptidase IV prepared from pig liver and kidney

Dipeptidyl peptidase IV (dipeptidylpeptide hydrolase, EC 3.4.14.-) has been purified from the microsomal fraction of pig liver, using an immunoaffinity chromatography, and its properties compared with those of the enzyme purified from pig kidney. The amino acid compositions of both enzymes were similar. The same kinds of carbohydrates were found in both enzymes, but there were differences in the molar concentrations of individual sugars. The liver enzyme had greater concentrations of mannose, fucose and sialic acid than the kidney enzyme, while the concentrations of galactose and glucosamine were greater in the kidney enzyme. The carbohydrates accounted for approx. 18.3 and 22.7% of the weight of the kidney and liver enzymes, respectively. The pH optima, molecular weights, substrate specificities and Km values of the two enzymes and the effects of diisopropylfluorophosphate on their activities were nearly identical. The liver enzyme was heat- and pH-sensitive, but not attacked by proteinases.

Immunohistochemical localization of dipeptidyl aminopeptidase (DAP) IV in the rat submandibular gland during postnatal development

The localization of dipeptidyl aminopeptidase (DAP) IV in the rat submandibular gland during postnatal development was studied immunohistochemically using the unlabeled antibody enzyme method. Cryostat sections of rat submandibular glands were examined in animals 1 to 50 days old. In the first postnatal week, faint immunoreaction was detected in the apical region of the cytoplasm of terminal tubules. During the second postnatal week the reaction was gradually restricted to the luminal region of terminal tubules or developing acinar cells, and its intensity increased. The most striking change of the enzyme localization was observed in 15-day-old rats. At this time, DAP IV was confined to the luminal and lateral membranes of differentiated acinar cells and to the luminal membranes of intercalated and striated duct cells. This localization pattern was similar to that of the adult animal. DAP IV activity in the gland was also measured biochemically during the postnatal development. The results were in agreement with those of the immunohistochemical study. These results suggest that the localization of DAP IV is closely related to the postnatal differentiation and proliferation of acinar cells.