Spectrofluorimetric Study on the Weak Interaction between ATP and Na-4-Tosyl-L-arginine Methyl Ester Hydrochloride

In this paper, some new results on the selective weak interaction between Na-4-tosyl-L-arginine methyl ester hydrochloride （TAME） and adenosine-5＇-triphosphate （ATP） have been reported. Fluorescence spectrophotometry and Fourier transform infrared （FT-IR） spectroscopy were used to investigate this kind of weak interaction. In fluorescence experiments, obvious fluorescence quenching phenomena were observed when TAME was added, which indicated the weak interactions between TAME and ATP. It has been identified by fluorescence titration experiments that TAME exhibited high selectivity to ATP over ADP and AMP. FT-IR spectral results showed that an ATP-TAME adduct was formed. The experimental results indicated that the interaction sites were the guanidinium group of TAME main-chain and the γ-phosphate group of ATP, and the interaction took place through hydrogen bonding and electrostatic force. In addition, the effects of metal ions on the weak interaction between ATP and TAME, or between ATP and analogues of L-arginine were studied.

Fluorescent probes for recognition of ATP

Adenosine 5＇-triphosphate（ATP） not only participates in various physiological activities as the universal energy currency but also implicates in various pathological processes in living cells. Consequently,sensitive and selective detection ATP in live cells, tissues, as well as environmental samples, are urgently demanded. Due to the simple and convenient operation, economy cost, high selectivity for analyte, well biocompatibility and low cytotoxicity, fluorescent sensors for monitoring ATP have aroused great attention of researchers. In recent years, a large number of fluorescent sensors for detecting ATP have developed. This manuscript summarized most of these sensors and the interaction-mechanism between ATP and sensors, mainly including electrostatic interaction, p-p interaction, covalent bonding or hydrogen bond, or combinations of them, and the advantages of each strategy were also generalized.Here, a viewpoint of classification was shown where the sensors were divided into five typed ones according to the structure of probes used.

Sperm glyceraldehyde 3-phosphate dehydrogenase gene expression in asthenozoospermic spermatozoa

It has been suggested that the energy required for sperm motility is produced by oxidative phosphorylation while glycolysis seems to be an important source for ATP transmission along the flagellum. Some studies have investigated the chemical and kinetic properties of the enzyme glyceraldehyde 3-phosphate dehydrogenase to identify any changes in the regulation of glycolysis and sperm motility. In contrast, there are few studies analyzing the genetic basis of hypokinesis. For this reason, we investigated the glyceraldehyde 3-phosphate dehydrogenase gene in human sperm to evaluate whether asthenozoospermia was correlated with any changes in its expression. Semen examination and glyceraldehyde 3-phosphate dehydrogenase gene expression studies were carried out on 116 semen samples divided into two groups - Group A consisted of 58 normokinetic samples and Group B of 58 hypokinetic samples. Total RNA was extracted from spermatozoa, and real-time PCR quantification of mRNA was carried out using specific primers and probes. The expression profiles for the Groups A and B were very similar. The mean delta Ct was as follows - Group A, 5.79 ＋ 1.04; Group B, 5.47 ＋ 1.27. Our study shows that in human sperm, there is no difference in glyceraldehyde 3-phosphate dehydrogenase gene expression between samples with impaired motility and samples with normal kinetics. We believe that this study could help in the understanding of the molecular mechanisms of sperm kinetics, suggesting that hypomotility may be due to a possible posttranscriptional impairment of the control mechanism, such as mRNA splicing, or to posttranslational changes.