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.