Characteristics of Ca2+, Mg2+-dependent ATP hydrolysis in sperm cells of infertile men
Disturbances of fertilizing potential of spermatozoa are closely associated with dysfunction of ion-transporting ATPases, in particular Ca2+, Mg2+-АТРase. Reduced activity of tapsigargin-resistant and tapsigargin-sensitive Ca2+, Mg2+-АТРase leads to disruption of Ca2+-homeostasis and is characterist...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Львівський національний університет імені Івана Франка
2020-05-01
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| Series: | Біологічні студії |
| Subjects: | |
| Online Access: | http://publications.lnu.edu.ua/journals/index.php/biology/article/view/1120 |
| Summary: | Disturbances of fertilizing potential of spermatozoa are closely associated with dysfunction of ion-transporting ATPases, in particular Ca2+, Mg2+-АТРase. Reduced activity of tapsigargin-resistant and tapsigargin-sensitive Ca2+, Mg2+-АТРase leads to disruption of Ca2+-homeostasis and is characteristic for abnormal spermatozoa (pathoospermia). In order to study the peculiarities of action of Ca2+, Mg2+-АТРase, we determined the initial reaction rate, the maximum (plateau) amount of the reaction product and the characteristic reaction time. To determine these kinetic parameters of Ca2+, Mg2+-dependent hydrolysis of ATP catalyzed by Ca2+, Mg2+-ATPase, the dynamics of product accumulation of the ATP-hydrolases reaction was studied. The obtained curves were linearized in the coordinates {P/t; P}. Analyzing the changes in the activity of Ca2+, Mg2+-ATPase, the kinetics of primary-active transport of calcium ions through the plasma membrane and membranes of intracellular Ca2+-stores in saponin-permeabilized spermatozoa of infertile men was studied. It was shown that in normozoospermic samples, the transport of Ca2+ ions through the plasma membrane is characterized by a higher capacity than through the membranes of intracellular Ca2+-stores, but it occurs with practically the same initial velocity and characteristic reaction time. It was found that in pathospermic samples, transport of Ca2+ ions with the participation of both components of Ca2+, Mg2+-ATPase occurs less intensively and is characterized by a lower capacity compared to spermatozoa of men with preserved fertility. Specific changes in the kinetic parameters of Ca2+, Mg2+-dependent hydrolysis of ATP lead to inhibition of tapsigargin-resistant and tapsigargin-sensitive Ca2+, Mg2+-ATPase activity and cause a decrease in fertilizing potential of spermatozoa. |
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| ISSN: | 1996-4536 2311-0783 |