Question: The Oxus cobra contains what kind of ions for their venom to be active? 

<P0-S0> Ribonuclease V1 (RNase V1) is a ribonuclease enzyme found in the venom of the Caspian cobra ("Naja oxiana"). <P0-S1>  It cleaves double-stranded RNA in a non-sequence-specific manner, usually requiring a substrate of at least six stacked nucleotides. <P0-S2>  Like many ribonucleases, the enzyme requires the presence of magnesium ions for activity. <SEP> <P1-S0> The Caspian cobra ("Naja oxiana"), also called the Central Asian cobra, Oxus cobra or Russian cobra, a member of the family Elapidae found in Central Asia. <SEP> <P2-S0> The black-necked spitting cobra ("Naja nigricollis") is a species of spitting cobra found mostly in sub-Saharan Africa. <P2-S1>  They are moderately sized snakes that can grow to a length of 1.2 to in length. <P2-S2>  Their coloration and markings can vary considerably. <P2-S3>  They prey primarily on small rodents. <P2-S4>  They possess medically significant venom, although the mortality rate for untreated bites on humans is relatively low (~5–10%, in endemic regions under 1%). <P2-S5>  Like other spitting cobras, they can eject venom from their fangs when threatened (one drop over 7 m and more in perfect accuracy). <P2-S6>  The neurotoxic venom irritates the skin, causing blisters and inflammation, and can cause permanent blindness if the venom makes contact with the eyes and is not washed off. <SEP> <P3-S0> Ion chromatography (or ion-exchange chromatography) is a chromatography process that separates ions and polar molecules based on their affinity to the ion exchanger. <P3-S1>  It works on almost any kind of charged molecule—including large proteins, small nucleotides, and amino acids. <P3-S2>  The two types of ion chromatography are anion-exchange and cation-exchange. <P3-S3>  It is often used in protein purification, water analysis, and quality control. <P3-S4>  The water-soluble and charged molecules such as proteins, amino acids, and peptides bind to moieties which are oppositely charged by forming ionic bonds to the insoluble stationary phase. <P3-S5>  The equilibrated stationary phase consists of an ionizable functional group where the targeted molecules of a mixture to be separated and quantified can bind while passing through the column—a cationic stationary phase is used to separate anions and an anionic stationary phase is used to separate cations. <P3-S6>  Cation exchange chromatography is used when the desired molecules to separate are cations and anion exchange chromatography is used to separate anions. <P3-S7>  The bound molecules then can be eluted and collected using an eluant which contains anions and cations by running higher concentration of ions through the column or changing pH of the column. <P3-S8>  One of the primary advantages for the use of ion chromatography is only one interaction involved during the separation as opposed to other separation techniques; therefore, ion chromatography may have higher matrix tolerance. <P3-S9>  However, there are also disadvantages involved when performing ion-exchange chromatography, such as constant evolution with the technique which leads to the inconsistency from column to column.