Growth-related changes of parameters of the methylation cycle and jejunal aminopeptidase M in the rat

During development from juvenility to adulthood, rats displayed constant vitamin B12, decreasing folic acid and increasing homocysteine levels in blood plasma parallel to decreasing aminopeptidase M activities in the jejunum. The rising homocysteine level with advancing age implies growing metabolic stress and may be seen as cause for the increase of the number of cleft lip alveolus palate at pregnancies in higher age. Similarly, additional morphologic changes of the villi and crypta were regarded to reflect age-related adaptation of the digestive tract. Thus, the rat model is interesting for human-relevant studies of metabolic diseases or fetal anomalies, as in man these parameters develop likewise with increasing age. Sufficient supply of B vitamins is an important factor for a normal course of pregnancy, healthy offsprings and physiologic blood parameters and is essential to a stable methylation cycle.     

血清GPDA检测在多种恶性肿瘤诊断中的意义

目的:探讨血清甘氨酰脯氨酸二肽氨基肽酶(GPDA)检测在多种恶性肿瘤诊断中的意义.方法:采用日立7150型全自动生化分析仪动态分析法测定118例各种肿瘤患者以及112例正常人血清中的GPDA活性.结果:74.1%的肺癌,72.2%的胃癌患者血清中GPDA活性显著低于正常组(P＜0.01);71.4%肺癌肝转移,66.7%胃癌肝转移,69.4%原发性肝癌患者血清中GPDA活性显著高于正常组(P＜0.01);而肝血管瘤患者血清中GPDA活性在正常范围(P＞0.05).结论:GPDA活性检测可以为胃癌,肺癌以及原发性肝癌的临床诊断与鉴别诊断提供依据,同时对监测恶性肿瘤肝转移具有重要意义.     

Associations of ERAP1 coding variants and domain specific interaction with HLA-C106 in the early onset psoriasis patients of India

Interferon-γ-induced aminopeptidase ERAP1 trims peptides within the endoplasmic reticulum so that they can be loaded onto MHC class I and presented to the CD8⁺ T-cells. ERAP1 association and its interaction with HLA-C106 is controversial across different populations. We have investigated the association and possible functional role of non-synonymous SNPs at different exons of ERAP1 (rs26653: Arg127Pro, rs30187: Lys528Arg and rs27044: Gln730Glu) and their interactions with HLA-C106 in psoriasis. Significant associations of HLA-C106 (OR = 5.47, P < 2.2 × 10^?16), rs30187 (OR 1.35, P = 7.4 × 10^?4) and rs27044 (OR = 1.24, P = 5.8 × 10^?3) were observed. All three ERAP1 SNPs showed significant association only for HLA-C106 positive patients, while rs30187 and rs27044 showed significant association only for early onset patients (rs30187: OR = 1.47, P = 9.6 × 10^?5; rs27044: OR = 1.36, P = 3.3 × 10^?4). No differential expression of ERAP1 was observed either between paired uninvolved and involved skin tissues of psoriasis patients or between non-risk and risk variants in the involved skin. Significant epistatic interaction was observed between HLA-C106 and the SNP (rs27044) located at the peptide-binding cavity of ERAP1. Evolutionary conservation analysis among mammals showed confinement of Lys528 and Gln730 within highly conserved regions of ERAP1 and suggested the possible detrimental effect of this allele in ERAP1 regulation.     

脊髓损伤后大鼠甘氨酰脯氨酸二肽氨基肽酶的表达及甲基强的松龙干预后的变化

目的：研究大剂量甲基强的松龙对脊髓损伤后甘氨酸脯氨酸二肽氨基肽酶（glycylproline dipeptidyl aminopeptidase,GPDA）基因表达变化的影响。方法：Sprague-Dawley大鼠36只。将所有大鼠随机分为三组,假手术组、脊髓损伤未使用药物干预组（创伤组）、脊髓损伤＋甲强龙干预组（甲强龙组）。在大鼠脊髓损伤后24h将损伤的脊髓组织切取,进行逆转录PCR反应并检测GDPA的表达。结果：假手术组GDPA的mRNA的表达的相对丰度为1.5403±0.1604;脊髓损伤24h后创伤组GDPA的表达的相对丰度为0.5994±0.3414,与假手术组相比差异有非常显著统计学意义（P〈0.01）;GDPA在脊髓损伤后使用甲强龙干预组中的表达相对丰度为1.8432±0.1294,与创伤组比较差异有非常显著统计学意义（P〈0.01）。结论：大剂量甲基强的松龙的早期使用能促进脊髓损伤后甘氨酸脯氨酸二肽氨基肽酶的表达恢复,发挥细胞保护作用。     

Small molecule inhibitors of methionine aminopeptidase type 2 (MetAP-2) fail to inhibit endothelial cell proliferation or formation of microvessels from rat aortic rings in vitro

The protein processing enzyme, methionine aminopeptidase-2 (MetAP-2), has been identified as a molecular target of fumagillin and its derivative, TNP-470, compounds known to inhibit endothelial cell proliferation and angiogenesis. A high-throughput screening program was undertaken to identify selective, reversible inhibitors of MetAP-2 in an attempt to discover structurally novel anti-angiogenic agents for potential therapeutic use in oncology. Approximately 90 small-molecule, reversible, selective inhibitors of rhMetAP-2 were identified. The most potent of these compounds contained a singly-substituted triazole moiety which exhibited an IC₅₀ of 8 nM (95% confidence limits 5 to 13 nM) and was highly selective for MetAP-2 over MetAP-1 ( 60-fold difference in IC₅₀ values). Unlike fumagillin, these MetAP-2 inhibitors failed to significantly inhibit growth factor-stimulated endothelial cell (HUVEC) proliferation or to suppress angiogenesis in the in vitroaortic ring explant model of microvessel outgrowth. The MetAP-2-inhibitory activity of these compounds was dependent on the divalent cation used as the metalloenzyme activating cofactor for MetAP-2. These inhibitors were identified using cobalt(II)-activated recombinant human MetAP-2 for screening compound libraries. When manganese (Mn²⁺) was substituted for cobalt following EDTA treatment and extensive dialysis of the MetAP-2 protein, these inhibitors were significantly less potent (40-fold increase in IC₅₀) as inhibitors of MetAP-2. These results support the recent hypothesis that cobalt may not be the relevant divalent metal ion cofactor for MetAP-2 in cells and may explain the observed absence of cell-based activity using potent triazole inhibitors of cobalt-activated MetAP-2     

Significance of the Measurement of Urinary Alanine Aminopeptidase and N-Acetyl-β-D-Glucosaminidase Activity in Evaluating Patients with Essential Hypertension

To examine the relationship between the urinary levels of alanine aminopeptidase (AAP) or N-acetyl-β-D-glucosaminidase (NAG) and the advance of essential hypertension, we measured the urinary levels of these enzymes in 20 normotensive controls, 8 subjects with borderline hypertension and 40 subjects with WHO stage I and stage II essential hypertension. The urinary level of NAG in stage II hypertensives was higher than that in the normotensives, and borderline or stage I hypertensives (p < 0.01). Systolic blood pressure and the urinary level of NAG was positively correlated in hypertensives (rs=0.43, p < 0.01). The urinary level of NAG was correlated inversely with renal blood flow (rs=-0.61, p < 0.01). The urinary level of AAP in stage II hypertensives was also higher than that in the normotensives (p < 0.01) or stage I hypertension (p < 0.01), but the urinary AAP level was not significantly correlated with systolic blood pressure or renal blood flow in hypertension.     

Effect of adrenalectomy on rat epididymidis

Aim: To investigate the effect of adrenalectomy (ADX) on the epididymidis of Sprague-Dawley rats. Methods: The histological, biochemical (cholesterol protein, zinc, copper, alkaline and acid phosphatase aryl sulphatase, lactic dehydrogenase and leucine amino peptidase) and hormonal (FSH, LH and testosterone) changes of caput and cauda epididymis in ADX rats were observed. Results: Organ wet weight, histological studies and morphometric measurements indicated a cellular degeneration in caput and cauda epididymis of ADX rats. Serum testosterone level was significantly lower in ADX than in sham-operated rats, while the serum FSH and LH were below the detection limit of 1 mIU/mL. The enzymatic activity was higher in ADX than in sham-operated rats. Epididymal zinc level increased whereas copper level decreased in ADX rats compared to the sham-operated. Conclusion: Adrenalectomy leads to degeneration of caput and cauda epididymidis epithelial cells as a result of decreased supply of testosterone. (Asian J And     

Effects of three peptidase inhibitors, amastatin, captopril and phosphoramidon, on the hydrolysis of [Met5]-enkephalin-Arg6-Phe7 and other opioid peptides

The contents of [Met⁵]-enkephalin-Arg⁶-Phe⁷ (met-enk-RF) and its six hydrolysis products: Y, YG, YGG, YGGF, YGGFM, and YGGFMR were estimated after incubating met-enk-RF with either a guinea-pig ileal or striatal membrane fraction for various times at 37° C. After 45 min incubation with either ileal or striatal membranes, met-enk-RF was completely hydrolyzed, yielding Y as the major product. Incubation with either membrane preparation for 60 min in the presence of the aminopeptidase inhibitor amastatin hydrolyzed 90 or 92% of met-enk-RF, respectively, with YGG being the major product. If the dipeptidyl carboxypeptidase I inhibitor captopril is also included in the incubation, met-enk-RF hydrolysis decreases by about half for both membranes, with YGG remaining the major product. Inclusion of three peptidase inhibitors, amastatin, captopril, and phosphoramidon (inhibition of endopeptidase-24.11) further reduced met-enk-hydrolysis, with 87% or more remaining intact. This shows that met-enk-RF was mainly hydrolyzed by three enzymes, amastatin-sensitive aminopeptidase, captopril-sensitive dipeptidyl carboxypeptidase I and phosphoramidon-sensitive endopeptidase-24.11, in both ileal and striatal membranes. Additionally, estimations of [Leu⁵]-enkephalin (leu-enk), α- and β-neoendorphins (α- and β-neoends), and dynorphin B (dyn B) contents after incubating the individual peptides with striatal membrane for 60 min in the presence of the three peptidase inhibitors showed that 98, 32, 5, and 23%, respectively, remained intact. Our previous studies together with the data obtained here show that one group of endogenous opioid peptides: met-enk, leu-enk, met-enk-RF, met-enk-RGL, and dyn A-(1-8) are largely or almost exclusively hydrolyzed by the three enzymes, amastatin-sensitive aminopeptidase, captopril-sensitive dipeptidyl carboxypeptidase I, and phosphoramidon-sensitive endopeptidase-24.11, and indicate that an unidentified fourth enzyme(s) is involved in the hydrolysis of another group of peptides: α-neoend, β-neoend, and dyn B. Received: 15 July 1997 / Accepted: 20 November 1997     

Seminal Plasma Leucine Aminopeptidase in Male Fertility

Leucine aminopeptidase (LAP) enzymatic activity has been measured in the seminal fluid of a group of 119 males undergoing fertility check-up, and correlated with spermatic density. The results indicate that there exists a direct correlation between LAP activity in the seminal plasma and spermatic density. However, differences between the groups considered according to spermatic density are not significant. Seminal plasma mean leucine aminopeptidase is 40 times higher than that found in blood plasma.     

丹参、肌苷对犬热缺血肾γ——GT.LAP活性的影响

给犬(每组10条)静脉注射丹参(1g/kg)或肌苷(50mg/kg),钳夹左肾动脉60分钟后重新开放肾血流,丹参组和肌苷组缺血肾尿γ-GT、LAP活性明显低于对照组,丹参组与肌苷组之间则无明显差异。左肾缺血对血清和右肾尿γ-GT、LAP活性没有明显影响。本文对实验结果作了讨论。