diff --git a/examples/zkapps/04-zkapp-browser-ui/ui/src/pages/zkappWorkerClient.ts b/examples/zkapps/04-zkapp-browser-ui/ui/src/pages/zkappWorkerClient.ts
index bae123768..62e4d11c0 100644
--- a/examples/zkapps/04-zkapp-browser-ui/ui/src/pages/zkappWorkerClient.ts
+++ b/examples/zkapps/04-zkapp-browser-ui/ui/src/pages/zkappWorkerClient.ts
@@ -29,9 +29,9 @@ export default class ZkappWorkerClient {
   async fetchAccount(publicKey58: string) {
     return this.remoteApi.fetchAccount(publicKey58);
   }
-  
-  async initZkappInstance(publicKey: PublicKey) {
-    return this.remoteApi.initZkappInstance(publicKey.toBase58());
+
+  async initZkappInstance(publicKey58: string) {
+    return this.remoteApi.initZkappInstance(publicKey58);
   }
 
   async getNum(): Promise<Field> {