A detailed description of the spike glycoproteins of SARS-CoV-2 reported that two binding subunits can be distinguished. These subunits become active when the two units are cleaved by host cell proteases on the host cell membrane. Subunit, S1 is responsible for binding to the host cell membrane and subunit, S2 is responsible for fusion of the virion and host cell membranes. The S1 unit is the factor that makes various coronaviruses specific toward a certain host [8]. Pulmonary angiotensin-converting-enzyme 2 (ACE-2) in humans exhibit the appropriate receptor, a specific sequence of amino acid residues [9], towards S1 and partly explains the effective spread of the coronaviruses via droplets in the atmosphere [10].