Enzymatic characterization of arginine esterase from dog seminal plasma

Some more about dogs: Proteomics of neglected biological fluids

We report in this manuscript what is known about the protein makeup of a selection of biological fluids in the domestic dog. The samples we review - amniotic and allantoic fluid, seminal fluid, saliva, bile, synovial fluid, tears - are still very poorly characterized in this species. For some of them we can present results from our own, mainly unpublished experiments. SIGNIFICANCE: The dog is one of the most widespread companion animals, and also of medical relevance as model species for some human diseases. Still, investigation of body fluids other than serum and urine is not so commonly undertaken, although - like in humans - also these sample types may have potential for diagnostic purposes. We compile published data about proteomes of fetal fluids, seminal plasma, saliva, bile, synovial fluid and tears, enriched by some yet unpublished data of our own (proteins of amniotic and allantoic fluid, tears). Closing gaps in our knowledge on dog proteins will further our understanding of (patho)physiological processes.

Rhodesian Ridgebacks have an increased risk to develop benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is an age-dependent primarily non-inflammatory enlargement of the accessory gland in the intact dog. The aim of the present study was to control a previously raised suspicion of a breed-related higher incidence of BPH in dogs of the Rhodesian Ridgeback breed. For this, 18 Labrador Retrievers/LR and 20 Rhodesian Ridgebacks/RR were assigned to the age groups 18-24 months (n = 12), 25-48 months (n = 13) and 49-72 months (n = 13). Prostate gland status was determined by rectal palpation, B-mode ultrasound, calculation of the prostate gland volume and semen analysis regarding haemospermia and was classified according to blood plasma concentrations of canine prostate-specific arginine esterase (CPSE) (normal ≤ 60 ng/ml, increased ≥ 61 ng/ml; Pinheiro et al., 2017). Concentrations of testosterone, 5α-dihydrotestosterone and estradiol were analysed in peripheral blood serum or plasma for detecting breed-specific conditions regarding the endocrine metabolism. Prostatic volume was significantly larger in RR irrespective of the CPSE status. In RR, BPH occurred more frequently and started at an earlier age compared with the LR. Breed-related specificities in steroid metabolism in the RR were indicated by correlations of 5α-dihydrotestosterone and estradiol with age and of testosterone with prostate gland volume. Although the incidence of sonographic signs of BPH and haemospermia did not fit with normal and increased CPSE concentrations, a breed-specific higher incidence of BPH in the RR breed could be clearly verified.

Amidolytic activities and prostate-specific antigen in human seminal plasma

The amounts of protein measured by absorbance at 280 nm, succinyl-L-alanyl-L-alanyl-L-prolyl-L-leucine-p-nitroanilide (Suc-Ala-Ala-Pro-Leu-pNA), D-valyl-cyclohexyl-alanyl-L-arginine-p-nitroanilide (Val-CHA-Arg-pNA), and glutamyl-L-phenylalanine-p-nitroanilide (Glu-Phe-pNA) amidolytic activities, and prostate-specific antigen (PSA) were measured in human seminal plasma (HSP) samples separated from the semen of 46 cases, including 13 cases of azoospermia and 33 cases of normozoospermia showing either good or poor quality of liquefaction. There was a highly significant correlation between the concentrations of all amidolytic enzyme activities studied and the concentration of PSA in HSP samples (p<.01). The HSP sample volume showed a relatively good negative coefficient of correlation to all items measured (p<.01) with the exception of protein concentration. The Suc-Ala-Ala-Pro-Leu-pNA, Val-CHA-Arg-pNA, and Glu-Phe-pNA amidolytic activities in azoospermia HSP samples were 2.33. 1.68, and 1.43 times higher, respectively, than those of normozoospermia samples showing good quality liquefaction. After the addition of morphologically purified human sperm to HSP sample of azoospermia cases, the Suc-Ala-Ala-Pro-Leu-pNA amidolytic activity in the HSP sample of azoospermia was not decreased for up to 18 h incubation, while the number of motile human sperm gradually declined, and no motile human sperm were detected after 18 h of incubation. The high Suc-Ala-AlaPro-Leu-pNA amidolytic activity in HSP samples of azoospermia cases did not result from a lack of motility.

Fibrinogen-like substance and thrombin-like enzyme in seminal plasma: coagulation system of human semen

This investigation was conducted to examine the presence of fibrinogen-like substance and thrombin-like enzyme in human semen (human seminal plasma) after liquefaction. The human seminal plasma contained small amounts of respective substances which are absorbed on anti-fibrinogen and anti-thrombin III affinity columns, respectively. The thrombin-like enzyme with Gly-Pro-Arg-pNA amidolytic activity was inhibited by human seminal plasma trypsin-like enzyme inhibitor (HSP-TI) and antithrombin III. The fibrinogen-like substance reacted with the thrombin-like enzyme, forming a fibrin-like substance. It would appear that certain aspects of the coagulation process in human semen constitute the same process as the final stage of the blood coagulation system.

Evaluation of serum and seminal plasma markers in the diagnosis of canine prostatic disorders

Serum and seminal plasma concentrations or activities of acid phosphatase (AP), prostate specific antigen (PSA), and canine prostate specific esterase (CPSE) were measured in normal dogs, dogs with benign prostatic hyperplasia (BPH), dogs with bacterial prostatitis, and dogs with prostatic carcinoma to determine if these assays would be of value in differentiating dogs with prostatic carcinoma from normal dogs, and dogs with other prostatic disorders. In addition, tissue sections of prostatic adenocarcinomas were stained with antiprostatic AP, anti-CPSE, and anti-PSA antibodies to determine if these would be suitable immunohistochemical markers of prostatic carcinoma. Prostate-specific antigen was not detected in canine serum or seminal plasma. Serum and seminal AP activities did not differ significantly between normal dogs and those with prostatic diseases, or among dogs with different prostatic disorders. Serum CPSE activities were significantly higher in dogs with BPH than in normal dogs. Mean serum CPSE activities in dogs with BPH, bacterial prostatitis, and prostatic carcinoma were not significantly different from each other. Slight to moderate immunohistochemical staining of canine prostatic adenocarcinomas was noted for prostatic AP and PSA; most tumors did not stain for CPSE. These results show that proteins of prostatic origin appear in the serum of dogs as a result of prostatic pathology, especially BPH. Canine prostatic adenocarcinoma does not appear to be associated with significant increases in CPSE or AP activities, possibly because of down-regulation of these enzymes by prostatic carcinoma cells. It is also possible that failure to detect significant differences resulted from limited statistical power for some groups and pairwise analyses because of the small number of dogs evaluated.

Detection and separation of some arginine amidases including tissue kallikrein from human seminal plasma

A plasminogen/plasmin like substance (AHSAA-1), with affinity to lysine column was separated from DEAE-cellulose adsorbed human seminal plasma. Two forms of acidic arginine amidase with different affinities to LBTI (AHSAA-2) and aprotinin columns (AHSAA-3) were separated from the DEAE-cellulose adsorbed preparation and AHSAA-3 was identified as tissue kallikrein. Two basic arginine amidase preparations having affinity to LBTI (BHSAA-1) and aprotinin column were also separated from the CM-cellulose adsorbed human seminal plasma. Three basic arginine amidases with different molecular mass (BHSAA-2 to 4) were separated by Cellulofine GCL-2000 gel filtration from aprotinin adsorbed material and some of their properties were examined.

Basic arginine esterase from human seminal plasma: purification and some properties

Basic arginine esterase (amidase) with a specific activity of 3.2 mumol N-alpha-tosyl-L-arginine methyl ester (Tos-Arg-Me) esterolysis per A280 was purified about 230-fold from a CM-cellulose absorbed preparation of human seminal plasma. The purified enzyme was a single band with an apparent molecular weight of 3.4-4.1 x 10(4). The amidolytic activity of this enzyme was suppressed by aprotinin, soybean trypsin inhibitor (SBTI), leupeptin, and antipain, while alpha 1-antitrypsin, ovomucoid trypsin inhibitor (OTI), EDTA, and chymostatin had no or weak effect. This enzyme hydrolyzed synthetic basic amino acid derivatives and N-alpha-tosyl-glycyl-L-prolyl-arginine-p-nitroanilide (Tos-Gly-Pro-Arg-pNA) and N-alpha-tert-butyloxycarbonyl-L-leucyl-L-prolyl-L-arginine-p-nitroanilid e (Boc-Leu-Pro-Arg-pNA) were the best substrates. The enzymatic characteristics of present enzyme were clearly different from tissue kallikrein, acrosin, and seminin in human semen.

Characterization and expression of the prostatic arginine esterase gene, a canine glandular kallikrein

The prostatic arginine esterase gene was isolated from a genomic library prepared with dog liver DNA in lambda EMBL3. The selected clone contained an insert of approximately 17 kb which included the whole coding portion of arginine esterase mRNA (5 exons plus 4 introns), 2 kb upstream from the initiation site and 12 kb downstream from the polyadenylation site. The intron-exon boundaries were identical to all known mammalian kallikrein genes. The deduced amino acid sequence indicated a high degree of identity (51-61%) with other kallikreins expressed not only in the prostate but also in the pancreas of various animal species. The 5'-flanking sequences contained potential regulatory elements such as a variant TATA box (TTTAAA), a CCAAT box, a SP1 transcriptional factor binding site (GGGCGG), and two TGTCCT motifs resembling glucocorticoid response elements. Southern blot analysis with an amplified cDNA fragment of 487 bp corresponding to the 5' portion of the mRNA and with a DNA probe from a different portion of the arginine esterase gene indicated the presence of two to three homologous genes in the canine genome while in a previous study a single band was detected using a 400-bp arginine esterase cDNA corresponding to the 3' portion of the mRNA. These results suggest that the arginine esterase gene belongs to a small kallikrein gene family. Arginine esterase mRNA is expressed primarily in the prostate but also at an extremely low level (approximately a thousandfold less) in several other tissues including the liver, the gracilis thigh muscle, the kidney, and the pancreas.

Effects of androgen and antiandrogen treatment on canine prostatic arginine esterase

A series of experiments were conducted to investigate the regulation of the primary secretory protein of the canine prostate, arginine esterase, by androgens and/or new antiandrogen under development. In the first experiment, castration decreased (P less than 0.05) prostatic arginine esterase levels relative to intact controls (0.26 +/- 0.1 and 17.0 +/- 0.1 mumole/min/mg protein, respectively). Treatment of castrate dogs with either 5, 10, or 20 silastic capsules (8 cm length) containing the androgen 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-diol) plus 1 capsule containing estradiol-17 beta (E2) or the i.m. injection of 25 mg 3 alpha-diol and 0.25 mg E2 for 12 weeks resulted in a dose-dependent increase (P less than 0.05) in prostatic arginine esterase activity (6.8 +/- 1.7, 19.0 +/- 3.6, 21.3 +/- 0.9, and 14.2 +/- 0.7 mumole/min/mg protein, respectively). In the second experiment, steroid treatment (10 3 alpha-diol plus 1 E2 silastic capsules) of castrate dogs for 12 weeks resulted in prostatic arginine esterase activity of 17.8 +/- 2.3 mu mole/min/mg. Co-administration of the steroidal androgen receptor antagonist. Win 49,596 (WIN) at doses of 0.625, 2.5, 10, or 40 mg/kg/day p.o., dose-dependently inhibited (P less than 0.05) prostatic arginine esterase activity (14.9 +/- 1.1, 14.3 +/- 1.3, 3.4 +/- 1.9, and 0.21 +/- 0.1 mumole/min/mg, respectively) to levels similar to that observed in castrate controls (0.14 +/- 0.03 mumole/min/mg). Administration of the nonsteroidal androgen receptor antagonist flutamide at 10 mg/kg/day p.o. to steroid-induced dogs also inhibited (P less than 0.05) arginine esterase activity (0.07 +/- 0.02 mumole/min/mg). In the last experiment, treatment of intact dogs with WIN at 0.625, 2.5, 10, and 40 mg/kg/day for 16 weeks dose-dependently reduced (P less than 0.05) arginine esterase levels (17.0 +/- 1.0, 16.3 +/- 1.5, 10.2 +/- 1.2, and 3.9 +/- 2.5 mumole/min/mg, respectively) compared to intact controls (14.4 +/- 1.2 mumole/min/mg). Histomorphologic and ultrastructural evaluation of prostates from dogs indicated that antiandrogen treatment resulted in glandular epithelial atrophy as well as a reduction in the number of secretory granules. The results of these experiments support that canine prostatic arginine esterase activity is under androgenic control, can be inhibited by antiandrogen treatment and may serve as a functional marker of the androgenic state of the prostate. Whether the effects of androgen and antiandrogens on prostatic arginine esterase is direct or indirect due to a general inhibitory effect on secretory epithelial cell function requires additional study. Furthermore, subject to further evaluation, the steroidal androgen receptor antagonist.(ABSTRACT TRUNCATED AT 400 WORDS)

Nucleotide sequence of the androgen-dependent arginine esterase mRNA of canine prostate

The nucleotide sequence of canine prostate arginine esterase mRNA was determined using a 400 bp cDNA clone and primer-extended cDNA transcripts for the 5'-coding and noncoding regions. The mRNA contains 864 nucleotides encoding a protein of 236 amino acids preceded by 24 amino acids which constitutes both the signal and the zymogen peptides. The sequence indicates the presence of one potential glycosylation site. A high degree of homology was found between the canine enzyme and other members of the kallikrein family including human prostate specific antigen. The protein appears to be specified by a single gene.

Radioimmunoassay in blood plasma of arginine esterase: the major secretory product of dog prostate

We have developed a radioimmunoassay to determine serum levels of arginine esterase, the major secretory product of the canine prostate. Although the antibodies recognized other related proteins in immunoblotting conditions, particularly in the pancreas, the radioimmunoassay appeared specific for arginine esterase of prostatic origin and reacted only slightly or not at all with cytosolic proteins from salivary glands, liver, skeletal muscles, and kidney. In serum samples, the sensitivity limit of the assay was about 2.5 ng per ml. The interassay and intraassay variations for serum samples that contained concentrations of arginine esterase ranging from 6 to 21 ng per ml were, respectively, 14% and 24%. Sera from 30 adult males and 14 adult females contained, respectively, 71 +/- 9 and 5.3 +/- 0.4 ng per ml. In a group of 12 dogs treated daily for 36-39 days with 50 micrograms of D-Trp6-luteinizing hormone-releasing hormone ethylamide, the concentrations of arginine esterase in the serum decreased progressively and became identical with those observed in the females. These results constitute the first evidence for the presence of a serum marker of the normal prostate in an experimental model. It should be particularly useful to test the effects of various agents on the prostate.

Purification and characterization of rat urinary esterase A1

An enzyme, esterase A1, which hydrolyzes tosyl-arginine methyl ester (Tos-Arg-OMe) was separated from esterase A2 and kallikrein of male rat urine and purified by a procedure involving ammonium sulfate fractionation, ion exchange chromatography, hydrophobic chromatography and gel filtration. The resulting preparation was apparently homogeneous, as assessed by polyacrylamide gel electrophoresis. The molecular weight of the preparation was estimated to be 27,000 by SDS-polyacrylamide gel electrophoresis and 30,000 by gel filtration. The enzyme was more specific for arginine methyl esters than for lysine methyl esters. The optimum pH determined with Tos-Arg-OMe as a substrate was 8.0 and the Km was 11.8 mM. The Tos-Arg-OMe esterolytic activity of esterase A1 was inhibited by soybean trypsin inhibitor, but not by aprotinin. In immunodiffusion analysis, the antiserum to esterase A1 formed immunoprecipitin arcs with this enzyme and the urine collected from rat bladder, but not with esterase A2, kallikrein, plasma and the urine collected from ureters. These results indicate that rat urinary esterase A1 differs from esterase A2 and kallikrein. The esterase A1 appears to be produced by accessory sex glands and excreted via the spermiduct into the urine.

Proteolytic activity of arginine esterase from dog seminal plasma towards actin and other structural proteins. Comparison with trypsin and kallikrein

At equimolar ratio of enzyme/substrate, actin, tropomyosin, fibronectin and myosin were extensively hydrolyzed during an incubation of one hour at 37 degrees C. Dog serum albumin, ovalbumin, bovine gamma-globulin and human prostatic acid phosphatase were not hydrolyzed. The activity of arginine esterase towards actin at pHs 6.5, 7.1 and 7.6 was respectively 60, 74 and 84% of the one found at optimum pH 8.2. The cleavage products of actin by arginine esterase and trypsin were similar although trypsin activity was 5000-fold higher. Kallikrein produced a major fragment of actin not observed with arginine esterase and trypsin. It is concluded that arginine esterase has a low trypsin-like activity towards structural proteins and that this activity may have a physiological significance.

Tissue kallikrein of human seminal plasma is secreted by the prostate gland

Samples of human seminal plasma were subjected to gel filtration, and the eluted fractions were analysed for their contents of tissue kallikrein-like antigen, arginine esterase activity and kininogenase activity. Two peaks of tissue kallikrein-like antigen were detected with apparent molecular masses of about 72 and 48 kDa. As judged by the criteria of molecular mass, immunoreactivity, kininogenase activity, identification of the released kinin as kallidin and inhibition studies, a genuine tissue kallikrein has been identified in the 48-kDa peak. In addition, this peak contains one or more species of immunoreactive tissue kallikrein which differ in molecular mass and enzymatic activities. The 72-kDa peak probably represents the complex of tissue kallikrein with alpha 1-proteinase inhibitor rather than a true high molecular mass tissue kallikrein. The prostate gland was identified as the site of origin of the tissue kallikrein in the seminal fluid by indirect methods and by demonstrating immunoreactive tissue kallikrein in prostatic tissue and secretion.