Proteins are made from long chains of smaller molecules called amino acids. These long chains are folded into particular shapes. This is important in relation to how antibodies and enzymes work. Enzymes are biological catalysts. There are optimum temperatures and pH values at which their activity is greatest.
It costs just $0.25 to send a text message from the U.S. to an international number. For customers who frequently send text messages to family or friends overseas, AT&Tâs International Long Distance Messaging package includes 100 text messages sent from the U.S. for $10 a month.
Cost per message: 20 cents each to send or receive (or less, if you sign up for a text messaging package); messages sent to international numbers cost 25 cents each. Text messaging packages start at $5 per month for 200 messages (10 cents for each additional message) and go up to $20 per month for unlimited texting. More information: AT&T text messaging. Sending email to an AT&T phone: Use the address format 10-digit-number@txt.att.net. Example: 4152221212@txt.att.net.