A Milan judge was arrested Friday in connection with what may prove to be the greatest of Italy's recent scandals: the government buyout in 1990 of the Enimont chemical corporation.

Italy's previous scandals have implicated top names in business, politicians and the mob. But the arrest Friday of Diego Curto extended the accusations of corruption to the judiciary as well. Until now, the judiciary has been seen as the guardian that uncovered the bribery and kickback scandal.But what most shocked Italians about the arrest of Curto, 68, was the allegation that he pocketed $250,000 in kickbacks as recently as July, roughly 16 months into the investigative frenzy in Italy, and only days after the apparent suicides of two principals in the case. Curto is the deputy head of the civil court and a principal commercial law judge in Milan, Italy's financial capital.

Curto, who is also a novelist and playwright, was detained in nearby Brescia, where magistrates have been investigating the case. This week Justice Minister Giovanni Conso ordered an administrative investigation into his role in the affair as well.

The charges against Curto involve abuse of office for personal enrichment, Milan officials said, and reflect the tangled web of financial, political and personal interests that have come to light.

The charges involve a November 1990 battle between the privately owned Montedison chemical company and its chairman, Raul Gar-dini, and the state-run chemical company that is known as ENI, for control of Enimont, their joint venture.

Investigators until now have been focusing on how ENI and its chairman, Gabriele Cagliari, together with ENI's owners at the Italian treasury, staved off a hostile takeover bid for Enimont by Gardini.