###### Abstract
Moreover, [PERSON] et al. have demonstrated that just 30 s irradiation of a sample containing red beet peroxidase and polyphenoxidase in 2450 GHz EMF (at 450 W microwave power) causes a very significant decrease in their enzymatic activity: namely, these authors observed 15-fold and 100-fold decrease in the activity of red beet peroxidase and polyphenoxidase, respectively [24]. The influence of EMF with extremely low frequency (ELF-EMF) can either stimulate or suppress the activity of enzymes. Therefore, [PERSON] et al. found that a number of membrane-associated enzymes (alkaline phosphatase, acetylcholinesterase-collageners from blood cell membranes, acetylcholinesterase-collageners from synaptosomes, phosphoglycerate kinase, and adenylate kinase) lose their activity upon the influence of a 75 Hz ELF-EMF, while other enzymes (CaATPase, Na/K ATPase, and succinic dehydrogenase) are virtually insensitive to such an influence [19]. [PERSON] et al. observed a 2-fold increase in the activity of cAMP-dependent protein kinase in human skin fibroblasts after 1 h exposure to 20 Hz ELF-EMF (7-8 mT) [20]. [PERSON] et al. demonstrated that the enzymatic activity of horseradish peroxidase (HRP) can either increase or decrease after its exposure to an extremely low frequency (1 to 50 Hz) rotating MF, depending on the MF parameters [25]. [PERSON] et al. [21] observed a -2-fold decrease in the HRP catalytic efficiency after its incubation in a 50 Hz (2.7 mT) ELF-EMF, while a 100 Hz (5.5 mT) ELF-EMF had virtually no effect on the enzyme. Modulation of the activity of enzymes by MFs can be explained by the interaction of the MF with the 3D structure of the protein [26]. The number of papers reporting the effects of electric and/or electromagnetic fields with picosecond rise-times on biological systems is quite low. Considering the cellular level, [PERSON] et al. [27] reported that an extremely high intensity pulsed electric field with 150 ps rise-time is able to permeabilize biological cells. In the works considering the influence of pulsed electromagnetic fields at the protein level, the studied range of pulse rise-times is limited to nanoseconds [28]. Application of pulsed electromagnetic fields (PEMF) with nanosecond rise-times was demonstrated to enhance the sensitivity of diagnostic systems [29]. Moreover, the possibility of the use of non-thermal effects of low-power (from \(10^{-5}\) to \(10^{-3}\) W/cm\({}^{2}\)) sub-nanosecond pulsed radiation (with a rise-time of 200 ps) for cancer therapy was reported [3]. Studies on the application of microwave imaging for cancer diagnosis are also reported [2,4,5]. In this connection, studying the effect of pulsed non-thermal electromagnetic radiation on enzymes represents an important task for both fundamental and applied research, including medical and diagnostic applications [3]. Sinusoidal electromagnetic fields of GHz frequency were reported to influence the activity of heme-containing enzymes [28]. We are, however, not aware of any studies reporting such an influence from pulsed electromagnetic fields with shorter (picosecond) rise-times; accordingly, additional research is required to investigate whether such fields have an influence on enzymes. Regarding pressure fields, they are also known to influence the structure and functionality of proteins [6] and enzymes [6,30,31,32,33]. Similar to electromagnetic radiation, the mechanical pressure, acting on biological objects, can be constant (hydrostatic) [6,30] or pulsed. The effects of hydrostatic pressure on enzyme systems were extensively studied previously. So, [PERSON] et al. [30] studied the impact of a constant 1000 to 3000 bar pressure on the properties of heme-containing enzymes and demonstrated that such an impact can lead to a change in their structure and functional activity. The latter case is very interesting with regard to studying electron transport systems, which participate in the metabolism of various compounds in the body [30].