natural human enzyme to defeat HIV

July 21, 2003

Hi All,

I thought you'd be intrigued by this article that notes a naturally occuring human enzyme that kills (or inhibits) HIV. The enzyme may occur at different levels in different people.

Emmanuel Segmen

Sabin Russell, Chronicle Medical Writer

Monday, July 21, 2003

Tiny protein could be big piece of AIDS puzzle Researchers are racing to find how Vif helps virus defeat immune system

In the microscopic world inhabited by the AIDS virus, scientists are uncovering a remarkable cloak-and-dagger struggle that pits the crafty microbe against an ancient antiviral defense wired into our genes. So far, the virus is winning. Still, the discoveries spilling out of molecular biology labs around the world are stirring new hope that basic research into the inner workings of HIV -- the virus that causes AIDS -- will reveal a weakness that can be exploited by a new generation of drugs. The latest and most exciting developments involve a tiny protein called Vif. Virion infectivity factor, or Vif, is produced using one of the smallest and least understood of the nine genes that make up the blueprint of HIV. Just a year ago, scientists probing the secrets of Vif reported two startling developments. They found that human cells contain a powerful enzyme known as APOBEC3G (pronounced APPO-beck) that can sabotage the genetic machinery of viruses similar to HIV. Simultaneously, they discovered that HIV itself has overcome this natural defense by using Vif to neutralize that protein.

HOT TOPIC FOR RESEARCHERS

These findings have sparked a race among AIDS researchers around the globe to learn more about Vif and the natural virus-killer it suppresses. "This is, without a doubt, one of the fastest-moving, most interesting areas of HIV biology right now," said Dr. Warner Greene, director of the Gladstone Institute of Virology and Immunology at UCSF. Greene's lab has been trying to unravel just how Vif disarms APOBEC. "We now know that human beings produce a natural anti-HIV protein," Greene said. "If we can somehow prevent Vif from doing its dirty work, we could unleash that protein." Evidence is mounting that APOBEC evolved in mammals to combat lentiviruses - - a family of slow-working but lethal viruses of which HIV is a member. But HIV itself has evolved its own counterweapon -- in the form of Vif. "It's a struggle for survival that has been forged between microbes and their hosts for eons," said Nathaniel Landau of the Salk Institute for Biological Studies in La Jolla. "We are only beginning to understand that struggle." Landau, who delivered a plenary speech at the International AIDS Society conference in Paris last week, reported in the July 11 issue of the journal Cell that the human APOBEC gene is different from that found in mice, green monkeys and rhesus macaques, but more closely resembles that found in chimpanzees. Landau speculated that different people may carry slightly different versions, and varying quantities, of the protective enzyme. "This could be one of the multiple factors that control the speed at which individuals develop disease," he said.

Read more at http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2003/07/21/MN186687.DTL

July 21, 2003

Emmanuel

I have a question for you on digestive enzymes. Why would protease, amylase and lipase from a vegetable source be active at low pH, while from pancreas destroyed by the acidity?

Alon