Promissory Note between Chaitan Khosla and Kosan Biosciences Incorporated dated September 22, 1999

Summary

Chaitan Khosla agrees to repay Kosan Biosciences Incorporated $71,500 plus 5.89% annual interest, with all amounts due by September 22, 2002. The loan is secured by a pledge of company stock and may be accelerated if Khosla leaves the company. If payment is late by 10 days or more, the full balance can become immediately due. Khosla may prepay at any time, and is responsible for collection costs if legal action is needed.

EX-10.20 12 ex-10_20.txt EXHIBIT 10.20 EXHIBIT 10.20 PROMISSORY NOTE $71,500 San Francisco, CA September 22, 1999 FOR VALUE RECEIVED, CHAITAN KHOSLA promises to pay Kosan Biosciences Incorporated (the "Company"), or order, the principal sum of seventy-one thousand, five hundred ($71,500), together with interest on the unpaid principal hereof from the date hereof at the rate of five and 89/100 percent (5.89%) per annum, compounded semiannually. Principal and interest shall be due and payable on September 22, 2002. Should the undersigned fail to make full payment of principal or interest for a period of 10 days or more after the due date thereof, the whole unpaid balance on this Note of principal and interest shall become immediately due at the option of the holder of this Note. Payment of principal and interest shall be made in lawful money of the United States of America. The undersigned may at any time prepay all or any portion of the principal or interest owing hereunder. This Note is subject to the terms of the Option, dated as of October 23, 1998. This Note is secured in part by a pledge of the Company's Common Stock under the terms of a Security Agreement of even date herewith and is subject to all the provisions thereof. The holder of this Note shall have full recourse against the undersigned, and shall not be required to proceed against the collateral securing this Note in the event of default. In the event the undersigned shall cease to be an employee or consultant of the Company for any reason, this Note shall, at the option of the Company, be accelerated, and the whole unpaid balance on this Note of principal and accrued interest shall be immediately due and payable. Should any action be instituted for the collection of this Note, the reasonable costs and attorneys' fees therein of the holder shall be paid by the undersigned. /s/ Chaitan Khosla ----------------------------------- Signature CHAITAN KHOSLA ----------------------------------- Print Name