Jam Master Jay

The American hip-hop DJ Jam Master Jay, who has been shot dead at his New York recording studio aged 37, was a member of Run-DMC, the first rap group to capture a worldwide audience; he was also responsible for popularising the idea of a DJ creating a musical collage for a song. His raps never embraced gun culture, instead promoting black awareness and education.

Run-DMC were formed by Joe Simmons and Daryl McDaniels in the early 1980s. They enlisted Jay (his real name was Jason Mizell), a musical child who had developed remarkable skills scratching and mixing records while DJing at teenage parties. All three had known each other since childhood in the middle-class black suburb of Hollis, New York, and, having graduated from St Pascal's Catholic school, they turned professional.

Immediately after signing to Profile Records in 1983 for an advance of $2,500, they scored a hit among young black Americans with their first single, It's LikeThat/ Sucker MCs. Their stripped-down sound - with only the rappers' voices, a drum machine and Mizell's percussive scratching of records on his turntable - invented modern hip-hop.

The band's preference for sportswear and tough street language gave the music its inner-city image. Their debut album was the first hip-hop to earn a gold plaque. Their 1985 effort, King Of Rock, also went gold.

Run-DMC then starred in Krush Groove, a fictionalised movie about their rise to stardom, promoted Martin Luther King's legacy, appeared on Sun City, the Artists United Against Apartheid record, and were the only hip-hop group invited to appear on Live Aid. Rick Rubin, a young white producer, produced their third album, Raising Hell (1986), making the rappers faster and sharper, and pushing Mizell's skills forward, thus giving the minimalist music a broader sonic palette. The album sold more than 4m copies.

Most importantly, Rubin teamed Run-DMC up with the heavy rock band Aerosmith to rerecord its 1975 hit, Walk This Way. He had noted how Mizell would DJ with old Aerosmith albums, artfully blending their heavy beats and loud guitars beneath the voices of Simmons and Mc Daniels. On the new version, Mizell and a drum machine became the rhythm section, and the song, accompanied by a distinctive video, became an international hit, won Run-DMC a white audience and revived Aerosmith's career.

A subsequent world tour with the Beastie Boys ensured their popularity, although the band was unfairly blamed for inciting violence after audience robberies at a Los Angeles concert.

None the less, Run-DMC became the first rap group to score a No 1 album on the R&B charts, the first to enter the US top 10 album charts, the first to have a video screened by MTV, the first to feature on the cover of Rolling Stone magazine, and the first non-athletes to endorse Adidas products - their single, My Adidas, helped popularise the trainer.

Yet success led to complacency, and the 1988 album Tougher Than Leather, accompanied by an abysmal film in which they starred, found Run-DMC deserted by their audience. The band continued to tour and issue infrequent albums, and Mizell made a name for himself as a producer for young hip-hop acts.

However, in 1998 Run-DMC topped the British charts for several weeks after Jason Nevins remixed It's Like That, although the dance music remix stripped out Mizell's contribution. He recently issued a two-volume video, Be A DJ, and in August opened the Scratch DJ Academy in New York, to teach "turntablism and DJ techniques".

He is survived by his wife and three children.

· Jason Mizell, 'Jam Master Jay', musician, born January 21 1965; died October 30 2002

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