Professor Daniel Koshland’s family was big into jeans. But he was always more interested in genes.

The biochemist, whose groundbreaking work with enzymes led to the creation of cancer-treatment drugs, also spent a decade editing Science magazine and was a champion of Jewish and Israeli causes. At 86, he still ran an active lab at U.C. Berkeley, and earned two patents last year.

“He had a passion for science that drove everything. He was one of those wonderfully lucky people who found an interest in life early on that sustained him until he died,” said daughter-in-law Catherine Koshland, a professor and vice provost at Berkeley, where Daniel Koshland was a campus fixture since 1965.

Koshland died in a Walnut Creek hospital Monday, July 23, following a stroke. He was 87.

His father, Daniel Sr., partnered with the elder Walter Haas to make Levi Strauss into a household name. And while the younger Koshland’s intelligence was obvious early on, so was his penchant for the sciences.

The elder Koshland was a pillar of the Bay Area Jewish community, and Daniel followed in his father’s footsteps here.

“His father was very involved in the Jewish community and with Israel. So I think he was brought up with it,” said Koshland’s son Jim, a past campaign chair for the S.F.-based Jewish Community Federation.

Koshland was a great champion of Israel’s Weitzman Institute and had ties to Ben Gurion University. The JCF’s Haas/Koshland Memorial Award, named for Walter Haas Sr. and Daniel Koshland Sr., allows a local student to study for a year in Israel.

“If you sat down with him casually, you’d have no idea this is a genius scientist. He was the most delightfully down-to-earth man,” said Wayne Feinstein, the JCF’s former executive vice president. The two met through the JCF and became good friends.

Phyllis Cook, the director of the Jewish Community Endowment Fund, described the Koshland family as, “Along with the Haas family, the leading supporters of the Jewish community for many years down to the present time.”

In Koshland’s lifetime of scientific work, he is perhaps best known for his theory of induced fit. Until several decades ago, the common perception was that certain proteins rigidly interacted with specific enzymes, fitting like a lock and key. Koshland discovered that proteins have the ability to reshape themselves depending upon which enzyme they encounter.

This knowledge gave scientists the ability to control the speed of chemical reactions or even if a chemical reaction occurs at all. Decades down the road, this led to the creation of cancer-treatment drugs.

Koshland and his first wife, Marian, a fellow U.C. Berkeley professor specializing in immunology, had five children.

“Amazingly, we never talked about science around the dinner table,” said Doug Koshland, the only Koshland child to go into the sciences (he’s a geneticist at Johns Hopkins University).

Marian died in 1997; a library is named after her on campus in the Valley Life Sciences Building. A few years later, Koshland bumped into Yvonne Cyr San Jule, whom he first got to know in a 1940 bacteriology class at Berkeley. They were married in 2000.

Although science was Koshland’s great love, it was not his only passion. He was a talented writer who treasured the fact that a story he wrote for a U.C. Berkeley periodical was praised by “Lust for Life” author Irving Stone. He edited Science magazine from 1985 to 1995, revitalizing the nation’s top scientific journal.

Friends and family recalled Koshland as a great storyteller and joker, whose sense of humor could diffuse even the prickliest situation. In the 1980s he spearheaded a move to combine 11 U.C. Berkeley scientific departments — and their 200 faculty members — into three larger groups. This involved moving people around campus, which created an uproar.

One day, a group of scientists met with him to protest. Without missing a beat, Koshland pulled aside one of the professors and noted that his work stunk, so he was being banished to a certain campus building. The language got a bit more colorful from there. But it was all an act, and the group was laughing uproariously by the time it was done. In the end, Koshland was able to reorganize Berkeley’s scientific departments, a move he ranked among his life’s greatest achievements.

Koshland is survived by his second wife, Yvonne Koshland, of Lafayette; son James Koshland of Atherton; daughter Ellen Koshland of Melbourne, Australia; daughter Phyllis (Phlyp) Koshland of Paris; daughter Gail Koshland of Tucson, Ariz.; and son Douglas Koshland of Baltimore. He is also survived by sisters Francis Geballe of Woodside and Phyllis Friedman of Hillsborough; stepchildren Elodie Keene, Philip Keene and Tamsen Calhoon; nine grandchildren; 12 stepgrandchildren; one great-granddaughter; and 17 step-great-grandchildren.

Donations in Koshland’s memory can be made to the Marian Koshland Science Museum, 500 Fifth St., NW, Washington, D.C. 20001, or to the U.C. Berkeley Foundation to support bioscience and energy teaching and research c/o Vice Chancellor-University Relations, 2080 Addison St., No. 4200, Berkeley, CA 94720.