LANGMUIR-BLODGETT MULTILAYERS OF POLYPEPTIDES

Poly( gamma -methyl-L-glutamate) (molecular weight, 46,000) and poly( gamma -benzyl-L-glutamate) (molecular weight, 28,000) were purchased from Sigma Chemical Co. Ltd. and dissolved in dichloroethane at a concentration of 0. 1-0. 2 mg ml** minus **1. They were spread onto a subphase of distilled deionized Millipore-filtered water held at a temperature of 19-21 degree C and a pH in the range 4. 8-5. 6 Langmuir isotherms were measured by compressing the spread film at 0. 05 nm**2 molecule** minus **1 min** minus **1. Langmuir-Blodgett films were deposited onto aluminum-coated silicon wafers by moving the sample vertically through the air-water interface at 0. 1 mm s** minus **1. The results illustrate the possibility of forming uniform stable polypeptide films deposited as Z layers. They agree with the model proposed by B. R. Malcolm to explain the unusual isotherms observed.